Part L Building Regulations 2011

Chris Arch

I still haven't bought a hard copy of the latest Technical Guidance Part L. I was comparing the new document online with my hardcopy from 2008. I found only differences in the building envelope which is now subject to higher thermal insulation. I also found that minimum standards are given for material alterations...

Honestly I have only read between the lines... Has someone had the opportunity to make an in-depth analysis yet?

Mellor

Is there not a version online that shows changes in red? As with other legal documents.
Possibly the draft plan and proposals

No6

Its all in the Carbon Coefficients, just try and get you designs to comply with the CPC and CEPC, or whatever they are actually called, the reference for compliance has gone down from 6 to 4.5, and I was finding 6 tough to comply with!!!

Any new house design will definately now need a DEAP assessment before it goes for planning just to make sure its compliant!!

Chris Arch

Mellor wrote: »

Is there not a version online that shows changes in red? As with other legal documents.
Possibly the draft plan and proposals

I haven't found anything like that online... But this would be very handy.

beyondpassive

Sinnerboy dug out this document which highlights the U-values needed for various build types

scroll down two thirds of the document to the landscape orientated page

http://www.environ.ie/en/Legislation/DevelopmentandHousing/BuildingStandards/FileDownLoad,23658,en.pdf

To achieve compliance, performance levels will generally have to be raised
significantly above the backstop value. This allows for selection of most appropriate means of increasing energy efficiency for each particular dwelling

There's a crazy anomaly, Part L compliance is easier for houses with high exposed surface area to floor area ratios. See attached, its alot easier for a big sprawing McMansion than a compact dwelling.


Part L surface area to volume.jpg

Chris Arch

No6 wrote: »

Its all in the Carbon Coefficients, just try and get you designs to comply with the CPC and CEPC, or whatever they are actually called, the reference for compliance has gone down from 6 to 4.5, and I was finding 6 tough to comply with!!!

Any new house design will definately now need a DEAP assessment before it goes for planning just to make sure its compliant!!

I was also finding it tough to comply, but the clients they could not believe it...

Honestly I was involved with only 2 houses since August 2009, both detached. For one house we used solar panels, with an air to air heat pump and a condensing gas boiler. Cavity walls insulated with 60mm koolthem in the cavity and 80mm Kooltherm internaly. Not talking about ground and roof insulation. We followed the approved construction details for thermal bridging and we were just limit with our CPC.

In the second house we used an air to water heat pump and compliance was achieved using 60mm Kooltherm within the cavity and only 25mm internally.

None of the dwelling had a great amount of glazing. We were using average 1.4 U-Value double glazing.

What will we need now? Has someone looked at the use of internal + external insulation with cavity blocks? Is it the end of double glazing replaced by triple glazing? Another new era has come. Even if extensions will be better insulated too… It is a shame that this new era arrives when only very few dwellings will be built.

beyondpassive

Any building applying for planning after 1st of December will need to comply. For Part L 2011 compliance for a Large detached 2 storey house, it is close to a passive type specification. Its scary how unprepared our building professionals, builders and 'drawin up plans men' are for the step change. Lucky for them we have no building control.

Example
280m2 house, 154m2 floor, 200m2 of wall,
U-Values required
Wall 0.15 , 250mm silver bead filled wide cavity, teplo ties. ( 150 cavity and dryling is plain stupid from a thermal mass view and dangerous from an interstitial condensation view. Thermal bridging results are also bad from this ridiculous solution plus you cant fix to it.
Floor 0.12 160mm PIR floor insulation.
Roof 0.12 340mm mineral wool
Windows 0.9 triple glazed 1.2 frame
Thermal bridging 0.08 y factor, quinnlite or EPS raft

6.5m2 of solar, 450l cylinder
91% efficient condensing gas boiler or 94% oil boiler
bag fed pellet stove as supplementary heating

Natural Ventilation, 3 extract fans, no chimney, draft lobby

worth noting this is worked out assuming an airtighness test of 5m3/hr/m and with Natural ventilation. It would be more significantly more cost effective to install MHRV and go for an airtightness of 1.5m3/nr/m2 than natural ventilation and a very bad airtighness result.

Chris Arch

beyondpassive wrote: »

Any building applying for planning after 1st of December will need to comply. For Part L 2011 compliance for a Large detached 2 storey house, it is close to a passive type specification. Its scary how unprepared our building professionals, builders and 'drawin up plans men' are for the step change. Lucky for them we have no building control.

Well... What the point to be prepared before the dead line? The essential is to comply, and so far the old method (2008) still does.

beyondpassive wrote: »

150 cavity and dryling is plain stupid from a thermal mass view and dangerous from an interstitial condensation view. Thermal bridging results are also bad from this ridiculous solution plus you cant fix to it.

Regarding thermal mass, I do not understand why you are so interested with it. It takes longer to heat up the room and there is a loss in the heating control as you may leave the room when the walls will still have accumulated the heat. I personely prefer a room that get warm fast.

The method of internal + cavity insulation was recommended by 2 of the largest insulation manufacturers in this country. Do you pretend that they have not carried out adequate testing? I have seen the cavity and internal insulation used in France too (about 20 years ago) and so far no problem with it.

beyondpassive wrote: »

It would be more significantly more cost effective to install MHRV and go for an airtightness of 1.5m3/nr/m2 than natural ventilation and a very bad airtighness result.

I find that my clients are very reluctant for using HRV in dwellings. In fact many of them are annoyed by the complexity involved with part L. I propose alternatives rather than impose one solution. I do not use the same system for every projects.

muffler

BryanF wrote: »

did you come here for a discussion or to lecture

Who are you referring to?

BryanF

muffler wrote: »

Who are you referring to?

ah i was having a go at what I perceived was an over the top amount of hostility but then decided it was none of my business:D

Chris Arch

Hi Brian... I was answering to "beyondpassive" not trying to lecture at all.

I am sure that the new regulations can be complied with using different insulation systems and not only the 250mm filled cavity. Same for roofs and floors.

In fact the amount of insulation necessary for compliance varies depending on the efficiency of the heating system required.

"beyondpassive" presented his system as a universal answer for compliance, but there was not a unique answer prior to 01/12/2011 and there will not be a unique answer after.

I was starting a conversation not lecturing anyone.

Chris Arch

beyondpassive wrote: »

Natural Ventilation, 3 extract fans, no chimney, draft lobby

You must be joking... Go and ask the average Irish familly if they want to live in a house without chimney...

Your design seems ok for appartments... Not for a house...

beyondpassive

Chris Arch wrote: »

Well... What the point to be prepared before the dead line? The essential is to comply, and so far the old method (2008) still does.

Topic is Part L 2011, I agree with you that compliance is overly complex and will get increasing more onerous.

Chris Arch wrote: »

Regarding thermal mass, I do not understand why you are so interested with it. It takes longer to heat up the room and there is a loss in the heating control as you may leave the room when the walls will still have accumulated the heat. I personely prefer a room that get warm fast.

In low energy houses, thermal stability leads to better thermal comfort and cheaper running costs. As an alternative to the ramp up/cool down method of heating it lends itself quite well to radiant heating and MHRV. For every calorie you put in the air you put 7 in the structure, it helps keep the house at 20 degrees year round and also if you have a thermal store and underfloor you can heat up your structure in Autumn from the solar panels. One of the most important uses though is to absorb and buffer summer solar gain.

Chris Arch wrote: »

The method of internal + cavity insulation was recommended by 2 of the largest insulation manufacturers in this country. Do you pretend that they have not carried out adequate testing? I have seen the cavity and internal insulation used in France too (about 20 years ago) and so far no problem with it.

I would be happy to dryline if it looked as it does on the Agrement certs, but composite drylining boards arent continuous insulation, thermally broken where they butt and with cut outs for wiring/back boxes and stops at wall and floor junctions, its a very haphazard job and lets the warm air in contact with cold block. The standard cavity died in 2007, dryling is a sticking plaster solution by the polymer board makers to keep the cavity wall on artificially life support.

Chris Arch wrote: »

I find that my clients are very reluctant for using HRV in dwellings. In fact many of them are annoyed by the complexity involved with part L. I propose alternatives rather than impose one solution. I do not use the same system for every projects.

Well said, every project is different and personal preferences do have a place.There is no 'one size fits all solution, but from designing alternative 'near passive' specifications there are common denominators, MHRV has become one of these. I'm personally an advocate of MHRV but subject to a ever increasing list of conditions.

Chris Arch

beyondpassive wrote: »

http://www.environ.ie/en/Legislation/DevelopmentandHousing/BuildingStandards/FileDownLoad,23658,en.pdf

Interesting

beyondpassive

Chris Arch wrote: »

You must be joking... Go and ask the average Irish familly if they want to live in a house without chimney...

Your design seems ok for appartments... Not for a house...

Not my design, based on a case study from DoEHLG regulatory impact document which tested the viability of the new Part L 2011. The house would have a flue for the stove which provides supplementary heating. I think you mean open fire, 2011 Part L will make it difficult to have open fires.

Be careful about giving clients exactly what they think they want or you'll end up with a design like Homer's car, (or mock georgian pastiche) :-)

some criticisms of part L from the RIAI here in their submission on the draft standard:
http://ebookbrowse.com/riai-final-submission-on-part-l-2010-main-document-doc-d32630776

Chris Arch

beyondpassive wrote: »

Not my design, based on a case study from DoEHLG regulatory impact document which tested the viability of the new Part L 2011. The house would have a flue for the stove which provides supplementary heating. I think you mean open fire, 2011 Part L will make it difficult to have open fires.

Be careful about giving clients exactly what they think they want or you'll end up with a design like Homer's car, (or mock georgian pastiche) :-)

some criticisms of part L from the RIAI here in their submission on the draft standard:
http://ebookbrowse.com/riai-final-submission-on-part-l-2010-main-document-doc-d32630776

Yes I meant an open fire. I could achieve compliance with it prior to the new regulations. I will need to find a way to do so with the new ones... But the way it goes, it seems that that even if I could, this will be definitely impossible in 2014....

Chris Arch

I was trying to purchase the hardcopy of the new technical guidance earlier today. I am told that the copies are not yet available...

It seems to me that it is not the designers that are not ready... How can we work with these new regualtions if they are not yet available?

mickdw

The lack of an open fire will certainly be a major issue for many people looking to self build.

Chris Arch

mickdw wrote: »

The lack of an open fire will certainly be a major issue for many people looking to self build.

Hi,

I think that it will be a major issue for anyone using a general building contractor or not...

About 1/6 of the dwellings that I have designed were self-built. 1/12 were designed without open fire.

creedp

Chris Arch wrote: »

Yes I meant an open fire. I could achieve compliance with it prior to the new regulations. I will need to find a way to do so with the new ones... But the way it goes, it seems that that even if I could, this will be definitely impossible in 2014....

Interesting discussion. It is clear that my build which has just recently been finished would have great difficulty qualifying under the new guidelines. When I look around at all the houses that have been build in recent years, very few would qualify and yet many of these houses are decent quality builds and efficient to run. Are we now in danger of almost heading into building facism in this country? It seems to be the case that you will not be allowed build within reasonable parameters any longer but do it this way or not at all! I understand why this push is on to improve the efficiency of builds but I 'd be off the view that we are now removing any element of individual choice and demanding that people toe the line to an extreme extent. Should it not be open to an individual to build within reason and suffer the consequences of this build design in terms of higher running costs? Look at the cars scenario, we don't insist you can't buy a gas guzzler but we make it expensive to do so.

I know this is a building forum so other comparators are moot and I have been ticked off for this before, but why is it in this society where we abhor the very limited consumption of fossil fuels for heating houses that we actively encourage people to travel the world in airplanes, we want to export/import huge and increasing quantities of product from all over the world - fancy a nice New Zealand wine anyone? 50", TVs and all sorts of technical gizmo's adorn houses, etc, etc, But the idea that someone might use electicity or oil to heat a house will bring on seriously negative comment. I'm not saying we shouldn't attempt to reduce waste every way possible but the almost extreme focus on heating houses is difficult to rationalise at times.

beyondpassive

Part L 2011 pdf download here
http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,27316,en.pdf

Good point creep, we've comparative neurotic standards on energy efficiency in the new build housing sector but do nothing to address energy in transport, in agriculture and embodied in the import of foods.

Its very noticable in many towns across Ireland that ad-hoc national planning policies have facilitated a flight of the middle class from towns to executive housing on country lanes. Apart from the added car trips this has generated it has a detrimental impact both on the urban social fabric and on the Landscape I think there should have been better controls on the visual design of one off housing, as most projects could have benefited greatly from the input of trained designers. It seems most people use surveys, engineers and drafts people to design houses and Architects didn't price themselves for this work. In a conspiracy of bad design, planners that assess schemes, don't have any design training, but impose twee victorian windows by misinterpreting rural housing design guidelines. So maybe there's a place of a wee bit of building facisim in the country, its starting to improve the quality of construction and workmanship and weed out some of the bad eggs and give the consumer a better, more sustainable product.

creedp

beyondpassive wrote: »

Part L 2011 pdf download here
http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,27316,en.pdf

Good point creep, we've comparative neurotic standards on energy efficiency in the new build housing sector but do nothing to address energy in transport, in agriculture and embodied in the import of foods.

Its very noticable in many towns across Ireland that ad-hoc national planning policies have facilitated a flight of the middle class from towns to executive housing on country lanes. Apart from the added car trips this has generated it has a detrimental impact both on the urban social fabric and on the Landscape I think there should have been better controls on the visual design of one off housing, as most projects could have benefited greatly from the input of trained designers. It seems most people use surveys, engineers and drafts people to design houses and Architects didn't price themselves for this work. In a conspiracy of bad design, planners that assess schemes, don't have any design training, but impose twee victorian windows by misinterpreting rural housing design guidelines. So maybe there's a place of a wee bit of building facisim in the country, its starting to improve the quality of construction and workmanship and weed out some of the bad eggs and give the consumer a better, more sustainable product.

Agree a little bit of facism can be a good thing especially when it comes to twee windows:) There is no doubt that better one off housing controls were required if nothing else to protect people from the worst excess of the consequences of their own decision making both for themselves, their neighbours and society in general. All I was saying is that there must be line somewhere between individual choice and big brother telling you exactly how to live your life.

Chris Arch

beyondpassive wrote: »

Part L 2011 pdf download here
http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,27316,en.pdf

Good point creep, we've comparative neurotic standards on energy efficiency in the new build housing sector but do nothing to address energy in transport, in agriculture and embodied in the import of foods.

Its very noticable in many towns across Ireland that ad-hoc national planning policies have facilitated a flight of the middle class from towns to executive housing on country lanes. Apart from the added car trips this has generated it has a detrimental impact both on the urban social fabric and on the Landscape I think there should have been better controls on the visual design of one off housing, as most projects could have benefited greatly from the input of trained designers. It seems most people use surveys, engineers and drafts people to design houses and Architects didn't price themselves for this work. In a conspiracy of bad design, planners that assess schemes, don't have any design training, but impose twee victorian windows by misinterpreting rural housing design guidelines. So maybe there's a place of a wee bit of building facisim in the country, its starting to improve the quality of construction and workmanship and weed out some of the bad eggs and give the consumer a better, more sustainable product.

RIAI architects have designed the large majority of housing estates during the boom this is why they were not interested with one off dwellings... It is only now that they have ravaged the Irish countryside and that their dwellings lay unfinished and unsold that they suddenly show interest for individual dwellings.

It is hypocrite from you to say that registered architects would have designed greener or more sustainable individual dwellings than non-registered architects. The fact is that the residential estates designed by RIAI were generally not as well insulated than individual houses designed by non-registered architects.

You are obviously lacking objectivity in your point of view.

What is your problem with the middle class living in large dwellings? Do you prefer the social classes to be reflected through architecture as it used to be and still is in most parts of the country? Why should the middle class be deprived from the comfort of upper-class? Why are you mixing social classes issues with sustainability ?.

Poor Uncle Tom

Chris Arch wrote: »

You are obviously lacking objectivity in your point of view.

:eek:

The words pot, kettle and black come to mind....

Every poster here is allowed to post their opinion as long as it is on-topic, your view point is as valid to you as the next persons it to them, please don't attempt to railroad your views over on others and don't lambaste others for their views and we will all get along nicely. Thank you.

beyondpassive

Chris Arch wrote: »

It is hypocrite from you to say that registered architects would have designed greener or more sustainable individual dwellings than non-registered architects. The fact is that the residential estates designed by RIAI were generally not as well insulated than individual houses designed by non-registered architects.

You've misrepresented me here, I agree with you on that point, All the big practices were churning out bad quality.

Chris Arch wrote: »

You are obviously lacking objectivity in your point of view.

Its an opinion, I'm open to that charge.

Chris Arch wrote: »

What is your problem with the middle class living in large dwellings? Do you prefer the social classes to be reflected through architecture as it used to be and still is in most parts of the country? Why should the middle class be deprived from the comfort of upper-class? Why are you mixing social classes issues with sustainability ?.

I put my hand up to being a hypocrite here. Like most Irish people, I want 250m2 on 2 acres with a bit of space between the neighbours. But if everyone who had the means, moved to a green field in the country (my business would boom) that would not be a good thing. However I recognise the fact that we have a vibrant rural population and that needs development. But that development needs to be managed. My own home town in Tipperary has been dramatically changed by middle class flight and out of town shopping. All that seems to be left is Chippers, bookies and late bars. Sustainability is the balance between society, economy and environment. I think our development policies or lack there-off didn't quite get that balance spot on.

Chris Arch

beyondpassive wrote: »

Like most Irish people, I want 250m2 on 2 acres with a bit of space between the neighbours. But if everyone who had the means, moved to a green field in the country (my business would boom) that would not be a good thing. However I recognise the fact that we have a vibrant rural population and that needs development. But that development needs to be managed. My own home town in Tipperary has been dramatically changed by middle class flight and out of town shopping. All that seems to be left is Chippers, bookies and late bars. Sustainability is the balance between society, economy and environment. I think our development policies or lack there-off didn't quite get that balance spot on.

You may find the following utopist or naive... But most Irish people, most French and English people, maybe the large majority of people dreams of a house with a view on the sea or a lake or a river... Jacques Fresco seems to say that buildings on the sea is the answer to a sustainable society...

I know that his theories lack consistence... But he proves that sustainability can surely be possible while giving people what they want. I agree with your critic of the planning system, specialy in rural areas. I am not an expert as you seem to be, but with sustainablity we need to look towards new ideas and not only through the DEAP. The full idea of sustainability must be reviewed within the all process, planning included. Part L seems to be restrictive to address the problem. I did read that it is also your opinion.

For the moment the term sustainability only rhymes with constraints and restrictions, maybe it is too early for architects to think about building in space or on the moon as I stated in another thread once, but what I really meant then, is that new technologies and sustainability should open the way to a new era, something like Fresco's vision.

Your previous post criticizing the middle class willing to live in comfortable dwellings appeared very retrograde, nearly feodal to me. If the middle class wants large dwellings with view on the sea, it should be permitted to have it. I am sure that if a Jaques Fresco complex was built in Irleand in the next couple of years, all the units would be sold before completion while many houses and appartments built these last 3 years would stay empty or unfinished.

Chris Arch

To keep the conversation within the subject of the new part L....

It is a shame that a hard copy of the new version of the regulations and that an update of the DEAP software are not yet available.

How can we design in compliance if the necessary tools aren't yet available?

No6

You can download the pdf and use a printer if you need a hard copy Chris. I suspect that you can use the current version of DEAP to design any houses you are doing but you will have to manually check the compliance with the new part L yourself. It should be available soon, after all its coming in on the first of december!!:eek:

Chris Arch

beyondpassive wrote: »

Any building applying for planning after 1st of December will need to comply. For Part L 2011 compliance for a Large detached 2 storey house, it is close to a passive type specification. Its scary how unprepared our building professionals, builders and 'drawin up plans men' are for the step change. Lucky for them we have no building control.

Example
280m2 house, 154m2 floor, 200m2 of wall,
U-Values required
Wall 0.15 , 250mm silver bead filled wide cavity, teplo ties. ( 150 cavity and dryling is plain stupid from a thermal mass view and dangerous from an interstitial condensation view. Thermal bridging results are also bad from this ridiculous solution plus you cant fix to it.
Floor 0.12 160mm PIR floor insulation.
Roof 0.12 340mm mineral wool
Windows 0.9 triple glazed 1.2 frame
Thermal bridging 0.08 y factor, quinnlite or EPS raft

6.5m2 of solar, 450l cylinder
91% efficient condensing gas boiler or 94% oil boiler
bag fed pellet stove as supplementary heating

Natural Ventilation, 3 extract fans, no chimney, draft lobby

worth noting this is worked out assuming an airtighness test of 5m3/hr/m and with Natural ventilation. It would be more significantly more cost effective to install MHRV and go for an airtightness of 1.5m3/nr/m2 than natural ventilation and a very bad airtighness result.

I am designing my first building (domestic extension) for compliance with the new part L.

The wall design as per above post does not make sense... Why did an official document came up with such option?

"Wall 0.15 , 250mm silver bead filled wide cavity, teplo ties."

The additional excavation work and concrete required for walls that wide are definitely not eco-friendly... Why to have a 250mm wall cavity when half this width can provide a similar U-value using the correct insulation?

archtech

Chris Arch wrote: »

I am designing my first building (domestic extension) for compliance with the new part L.

The wall design as per above post does not make sense... Why did an official document came up with such option?

"Wall 0.15 , 250mm silver bead filled wide cavity, teplo ties."

The additional excavation work and concrete required for walls that wide are definitely not eco-friendly... Why to have a 250mm wall cavity when half this width can provide a similar U-value using the correct insulation?

its just one solution to achieving compliance, there are others... timber frame, external insulation etc. many clients still want to see a cavity been built.

Eco-friendly would be everyone living in high density developments, with a good public transport system.

Chris Arch

archtech wrote: »

its just one solution to achieving compliance, there are others... timber frame, external insulation etc. many clients still want to see a cavity been built.

Eco-friendly would be everyone living in high density developments, with a good public transport system.

I was making reference to construction design rather than planning...

a wall with a 250mm cavity would require 1,350mm wide foundations. For a 100sqm bungalow, this represents 4.2 additional cubic metres of concrete and the same quantity of additional excavation.

I just cannot understand the advantage, if any, for such a design choice...

beyondpassive

Chris Arch wrote: »

I am designing my first building (domestic extension) for compliance with the new part L.

The wall design as per above post does not make sense... Why did an official document came up with such option?

"Wall 0.15 , 250mm silver bead filled wide cavity, teplo ties."

The additional excavation work and concrete required for walls that wide are definitely not eco-friendly... Why to have a 250mm wall cavity when half this width can provide a similar U-value using the correct insulation?

Hi Chris, a domestic extension doesn't need the above spec as it only needs to comply with backstop U-values not an EPC 60% better than 2005 regs DEAP calculated U-Values.

This is my own spec, it represents my interpretation of how to achieve compliance pls read the official document Regulatory impact assessment of part L 2010 here which dosent get into build types. http://www.environ.ie/en/Legislation/DevelopmentandHousing/BuildingStandards/FileDownLoad,23658,en.pdf

Its half meter wide wall, sure you can get 0.14 in to 250mm's , but the spec i've indicated is relatively foolproof and is block inside and block outside, as barry's tea and bacon+cabbage a solution to an Irish problem as your likely to get.

beyondpassive

Chris Arch wrote: »

I was making reference to construction design rather than planning...

a wall with a 250mm cavity would require 1,350mm wide foundations. For a 100sqm bungalow, this represents 4.2 additional cubic metres of concrete and the same quantity of additional excavation.

I just cannot understand the advantage, if any, for such a design choice...

Good point, but a 1m wide footing might well be enough to spread the loading, the three thirds rule is simply that, a rule of thumb. The above 1m of course would be subject to design by a structural engineer, just in case anyone is naive enough to size foundations from an Internet post. The new regs will make rafts and EPS rafts a more attractive option.

Its like the rugby union ELV's (experimental rules). Just when you've got the hang of the referee's interpretations, they change the rules again. ?? :-I

Chris Arch

beyondpassive wrote: »

Good point, but a 1m wide footing might well be enough to spread the loading, the three thirds rule is simply that, a rule of thumb. The above 1m of course would be subject to design by a structural engineer, just in case anyone is naive enough to size foundations from an Internet post. The new regs will make rafts and EPS rafts a more attractive option.
again. ?? :-I

Still not convinced... A structural engineer could design smaller foundations for any type of walls, not only this particular one.

Plus what does justify such width, such loss of space? You have failled to give us the advantages for using a 250mm cavity instead of a 125mm cavity that can provide for a similar 0.15 U-value.

Sorry to be so critical but I just cannot understand why this document favored this particular design. Is it that the insulation within the cavity is Irish made instead of being imported from abroad?

Chris Arch

beyondpassive wrote: »

Hi Chris, a domestic extension doesn't need the above spec as it only needs to comply with backstop U-values not an EPC 60% better than 2005 regs DEAP calculated U-Values.

Thanks, I knew that, but while looking at solutions for my extension I was also on the look at for a future dwelling to design when people will be able to borrow money from the banks for such ventures.

Dwelling design may become very rare for the next years to come... 2011 is the first year since 1997 that I have not been involved in the design of one or more dwellings. It is probably not the last one if I consider the Irish economy forecast...

sydthebeat

Chris Arch wrote: »

. Is it that the insulation within the cavity in Irish made instead of being imported from abroad?

Chris,
be careful how you post here.

we run a very tight ship and if you try to post from some hidden agenda, you will find yourself quickly banned from here.

Take this as a word of advice rather than a warning. If you have any questions as to how the forum is run, read the C+P charter

Chris Arch

sydthebeat wrote: »

Chris,
be careful how you post here.

we run a very tight ship and if you try to post from some hidden agenda, you will find yourself quickly banned from here.

Take this as a word of advice rather than a warning. If you have any questions as to how the forum is run, read the C+P charter

Sorry... I do not realise where I transgressed the rules... What hidden agenda are you talking about?

Was my question about the origin of the insulation in breach?

beyondpassive

Chris Arch wrote: »

Still not convinced... A structural engineer could design smaller foundations for any type of walls, not only this particular one.

Plus what does justify such width, such loss of space? You have failled to give us the advantages for using a 250mm cavity instead of a 125mm cavity that can provide for a similar 0.15 U-value.

Sorry to be so critical but I just cannot understand why this document favored this particular design. Is it that the insulation within the cavity is Irish made instead of being imported from abroad?

I'll repeat, the regulatory impact document didn't favour any particular design, read it please. 125mm PIR gets 0.15 under ideal test conditions in a lab, but in practice its lobbed in by blocklayers and performs only half as good. I work on buildings that perform exactly as designed. The bead is handy in that its just pumped in after the windows are installed and sealed. I like the option of installing the insulation before the outer leaf, but it can be tricky too.

Ya new build are like hens teeth and sometimes you feel you have to do a course a week to keep up with energy standards. SEAI and the BRE seem to get all my meagre fee income :-(

Chris Arch

beyondpassive wrote: »

I'll repeat, the regulatory impact document didn't favour any particular design, read it please. 125mm PIR gets 0.15 under ideal test conditions in a lab, but in practice its lobbed in by blocklayers and performs only half as good. I work on buildings that perform exactly as designed. The bead is handy in that its just pumped in after the windows are installed and sealed. I like the option of installing the insulation before the outer leaf, but it can be tricky too.

Ya new build are like hens teeth and sometimes you feel you have to do a course a week to keep up with energy standards. SEAI and the BRE seem to get all my meagre fee income :-(

Well... There are some tight rules here... I will try to continue this discussion within these rules... But still I am not sure yet why I was accused of a hidden agenda earlier...

I am not an expert in insulation... However, I am amazed by what you are telling me. We have an Irish agreement board, a British Agreement Board and so on. I am fully relying on those to design and certify my design.

Now you seem to say that tests carried out by these experts are not reliable because they are carried out in conditions that do not represent realistic situations... If so, what are they waiting for to change their testing technics?

Whatever, I am not fully convinced that their tests are not appropriate. In fact I have read similar accusation for an insulation, <SNIP> (if this is OK to name it). I tested this insulation over the rafters in a small bungalow in 2008 and the clients gave me a very good feedback about it, while many experts, probably working for other brands, claim that a 25 mm insulation cannot replace a 100mm layer.

PLEASE READ THE CHARTER
DO NOT NAME PRODUCTS OR COMPANIES ON THREAD.

Poor Uncle Tom

Chris Arch wrote: »

In fact I have read similar accusation for an insulation, <SNIP> (if this is OK to name it). I tested this insulation over the rafters in a small bungalow in 2008 and the clients gave me a very good feedback about it, while many experts, probably working for other brands, claim that a 25 mm insulation cannot replace a 100mm layer.

This reads like promotion of a product and if I had left the name in you could have been banned for spamming. Please read the charter before posting again.

Chris Arch

Poor Uncle Tom wrote: »

This reads like promotion of a product and if I had left the name in you could have been banned for spamming. Please read the charter before posting again.

I have read it... The product that I named is distributed in many countries the brand is international and I do not think that they need advertising from this board... Then as per the section 3.(a) from the charter that I copied below, I decided to insert it without any intent to advertise the product.

3.0 Naming of companies , bodies , individuals , products or services
3.(a) With the exception of large, national or multi-national businesses who really don’t need the free advertising , posts naming specific companies/traders and/or their products are discouraged and may be deleted and the poster warned or banned or both.

You must admit that there is not a clear line to dissociate the products that can be named to those that cannot. I had assumed that this product was OK to name, but I will not name it again.

Poor Uncle Tom

Chris Arch wrote: »

You must admit that there is not a clear line to dissociate the products that can be named to those that cannot. I had assumed that this product was OK to name, but I will not name it again.

To me it is extremely clear

posts naming specific companies/traders and/or their products are discouraged and may be deleted and the poster warned or banned or both.

If you can't comprehend this as well as getting an on-thread warning I will make it even clearer for you.

If you post the name of a company or product on thread again I WILL BAN YOU.

Now if you wish to continue argueing this take it to PM and do not derail this thread any more.

Chris Arch

To come back to the subject of this thread that was derailed here.

More specifically to come back on the issue of tests from the agreement boards that do not reflect the comportment of materials on the fields...

I do not know if these accusations are true or false... I have heard, especially for insulation, that some materials have the agreement boards certification but do not produce the specified performance. If this happens to be true, it should be easy to prove. If this is proved why are the materials still issued with the agreement boards certificates?

sinnerboy

Chris Arch wrote: »

I have heard, especially for insulation, that some materials have the agreement boards certification but do not produce the specified performance.

Not quite true. There is evidence from research into built structures that completed assemblies ( walls/floors/roofs) fail to perform thermally but the consistent finding is that poor workmanship and not "failing" insulation products is to blame.

Take the case of a partially filled cavity wall. If the boards are installed into the cavity with gaps which admit cold cavity air in behind the boards then the effectiveness of the insulation is devalued.

Agrement certificates give detailed design and construction advice together with lab test thermal performance of insulation materials.

Ignore the advice - you don't get the performance.

Chris Arch

sinnerboy wrote: »

Not quite true. There is evidence from research into built structures that completed assemblies ( walls/floors/roofs) fail to perform thermally but the consistent finding is that poor workmanship and not "failing" insulation products is to blame.

Take the case of a partially filled cavity wall. If the boards are installed into the cavity with gaps which admit cold cavity air in behind the boards then the effectiveness of the insulation is devalued.

Agrement certificates give detailed design and construction advice together with lab test thermal performance of insulation materials.

Ignore the advice - you don't get the performance.

OK... But then the problem is related to poor workmanship and this would be true for any insulation or any other elements of the building... It does not concern the material itself.

Poor workmanship is catastrophic in any situation whatever the materials used. A 250mm cavity would not solve the problem of poor workmanship.

The layered extra fine insulation that I cannot name is much easier to install than the conventional high density materials. However, I did read lots of critics about it not performing as per the tests that are carried out for the certificates. I have read some critics explaining that the tests were not carried out in a realistic context. I have tried it in a dwelling, it was fitted as per manufacturer's instructions and it works very well.

Whatever the product, it has to be fitted correctly to perform.

If Beyondpassive means that it is easier to correct bad workmanship with the 250mm cavity, then I understand his point. However, using a competent and conscientious builder maybe a more appropriate alternative.

If the tests consider the feasibility of installing correctly the materials on site, if installing the insulation for certified performance is a realistic option, then the builder or bricklayer only has to follow the instructions... It is the same for the rest of the construction work... If water pipes aren't insulated correctly then the building is not as efficient as it should. If the windows aren't sealed correctly then the building will be draughty...

If fitting the insulation on site to obtain the certified performance is not a realistic option, then the tests are misleading and they should be reviewed.

Mellor

Chris Arch wrote: »

a wall with a 250mm cavity would require 1,350mm wide foundations. For a 100sqm bungalow, this represents 4.2 additional cubic metres of concrete and the same quantity of additional excavation.

No it wouldn't.

Chris Arch

Mellor wrote: »

No it wouldn't.

You would keep your foundations to 1 metre width? I am talking of a basic dwelling here, one, two or three storey maximum; no piling involved.

Even with keeping the foundations to 1 metre wide, there is the thickness of the walls that are ... Bulky is the term I think...

Maybe some developers in the country would not mind to loose a foot in the width and another in the length... But I can guaranty that in Dublin they would, in any built up area, they would...

sydthebeat

Chris, you seem to be insisting on using a "rule of thumb" ahead of accepting calculated engineered solutions.

the sectional area of a 1350 x 450 foundation is 0.6075 sq m
the sectional area of a 900 x 300 foundation is 0.27 sq m

are you really saying that you honestly believe that the loading of a wall with a 250mm cavity is over 100% more than that of a wall with a cavity of 100mm ????
there must be very heavy air in the part of dublin you work in!!!

muffler

sydthebeat wrote: »

there must be very heavy air in the part of dublin you work in!!!

Smog?

Chris Arch

sydthebeat wrote: »

Chris, you seem to be insisting on using a "rule of thumb" ahead of accepting calculated engineered solutions.

the sectional area of a 1350 x 450 foundation is 0.6075 sq m
the sectional area of a 900 x 300 foundation is 0.27 sq m

are you really saying that you honestly believe that the loading of a wall with a 250mm cavity is over 100% more than that of a wall with a cavity of 100mm ????
there must be very heavy air in the part of dublin you work in!!!

First I must say that I am not an expert in this field. My understanding is that it is not only about the load but also about how it is spread on the foundations and on the ground.

I only design foundations for 2 or 3 storey building when the ground is not soft. The external wall designs that I use are either 2 skins of 100mm blocks with a 100mm or 110mm cavity or one skin of 215mm hollow blocks that I will probably not use anymore. In any other circumstances I would ask advice from a structural engineer.

I am aware of pile foundations and raft foundations... I have used piling in a project and I would like to be involved with a sandy ground where a raft could be appropriate. But I would not venture designing it myself.

If I was involved with a 250mm cavity project, I would first consult a structural engineer for the foundations. On the second project I would probably be able to use the same design and similar calculations.

I am looking at TGD Part A that will probably be updated next year. I do not want to get in too many details as I would find myself in trouble with the board charter again, but Diagram 11 of the regulations is the one that I generally use as well as table 1. I have also been advised on the concrete strength and other features such as steel reinforcement.

The subject of this thread is Part L… On a 10mx10m bungalow, a family could loose 6 sq m if using a 250mm cavity.

Chris Arch

sydthebeat wrote: »

there must be very heavy air in the part of dublin you work in!!!

Yea Heavy... if not the air... the tampo maybe... Or shall I say the beat...