Part L Building Regulations 2011

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...

sydthebeat

Chris Arch wrote: »

If I was involved with a 250mm cavity project, I would first consult a structural engineer for the foundations.

.... if so, then dont make a statement such as

a wall with a 250mm cavity would require 1,350mm wide foundations

not only does that border on a charter breach.. but its plain incorrect.

Chris Arch wrote: »

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

erm.. no... you keep the planned floor area, but build the cavity outwards.

Chris Arch

sydthebeat wrote: »

.... Originally Posted by Chris Arch


If I was involved with a 250mm cavity project, I would first consult a structural engineer for the foundations.

.... if so, then dont make a statement such as: a wall with a 250mm cavity would require 1,350mm wide foundations

I thought this was a discussion board... I discovered the government document with the 250mm cavity on this thread and as per TGD Part A it could require wider foundations.

sydthebeat wrote: »

.... erm.. no... you keep the planned floor area, but build the cavity outwards.

Well if this is your point of view, you must be working in the country and have obvioulsy no experience of what it is in Dublin or any other large town or city...

The price of the land has droped dramaticaly, but still it is difficult to find the space for descent dwellings in proximity to the centre. There are already plenty of cells in dublin that do not suit familly living. Within a dense area, the 250mm cavity will implicate smaller or fewer dwellings.

sydthebeat

chris, wall constructions generally have, and are becoming much thicker than the 310 cavity we're all used to.

2011 regs will probably require in most cases either:
200m plus cavity type
150mm cavity plus insulated plasterboard
external insulation of 200mm plus

all these construction types will equate to 400mm plus thick walls... regardless of what method choosen.... and regardless of what space you have to work with.


you have just stated

The external wall designs that I use are either 2 skins of 100mm blocks with a 100mm or 110mm cavity

well, that construction method simply wont cut it anymore.

Chris Arch

The 100mm fully filled cavity can provide a U-Valu of 0.16.

This U-value could be dropped to 0.14 while using 25mm of dabbed dry-lining.

Why wouldn't that be enough?

Of course I assume that the materials are fitted adequately and that the tests leading to the agreement board certificates are reliable.

This represent a 350mm to 360mm wall...

beyondpassive

Study here on various ways of testing insulation products and how multifoil manufacturers data should be interpreted


http://arrow.dit.ie/cgi/viewcontent.cgi?article=1033&context=engmas&sei-redir=1&referer=http%3A%2F%2Fwww.google.ie%2Furl%3Fsa%3Dt%26rct%3Dj%26q%3Dthesis%2520hot%2520box%2520testing%26source%3Dweb%26cd%3D1%26sq

roof insulation installation.jpg

See also roof installation image of insulation with m-foil, and quilt between rafters, well installed in 2007, but heating bills higher than expected and room drafty. The drafts were down to workmanship as there were gaps between the sheets where they lapped.

I like big insulation that can be poured rather than cut to fit. Foolproof.

Agrement don't test products, they just check that it is compliant in principle with building regs. I wouldn't ever expect to get below about 0.20 with 100mm of insulation in a cavity and would never dryline as it eliminates the useful mass storage.

roof insulation installation.jpg

Chris Arch

beyondpassive wrote: »

Study here on various ways of testing insulation products and how multifoil manufacturers data should be interpreted


http://arrow.dit.ie/cgi/viewcontent.cgi?article=1033&context=engmas&sei-redir=1&referer=http%3A%2F%2Fwww.google.ie%2Furl%3Fsa%3Dt%26rct%3Dj%26q%3Dthesis%2520hot%2520box%2520testing%26source%3Dweb%26cd%3D1%26sq

roof insulation installation.jpg

See also roof installation image of insulation with m-foil, and quilt between rafters, well installed in 2007, but heating bills higher than expected and room drafty. The drafts were down to workmanship as there were gaps between the sheets where they lapped.

I like big insulation that can be poured rather than cut to fit. Foolproof.

Agrement don't test products, they just check that it is compliant in principle with building regs. I wouldn't ever expect to get below about 0.20 with 100mm of insulation in a cavity and would never dryline as it eliminates the useful mass storage.

roof insulation installation.jpg

Sorry I had a quick look at the thesis on the foil insulation... But there was too many pages.

You say that Agreement boards do not test the products, but how do they know that these products comply with the regulations if they do not test them?

I have really no ideas on how these tests are carried out. But I know that different license are given for roof insulation, walls insulation, ground insulations and so on...

If as you say the agreement boards certificates aren't reliable... Then what is the point to have them and most of all, why aren't we changing the system?

I thought that we could rely on B.S. ... Are you guys pretending that British Standards are no more reliable than the Irish building control system? If so why was I taught to use them in my specifications?

sydthebeat

Chris Arch wrote: »

I thought that we could rely on B.S. ... Are you guys pretending that British Standards are no more reliable than the Irish building control system? If so why was I taught to use them in my specifications?

:rolleyes:

chris, mind your language..... i know english isnt your first language but that is no excuse for how you present yourself here.

There is no one here

pretending

anything, so be careful what you are insinuating.

If you do not understand something, get yourself eductated and draw your own conclusions based on the knowledge you aquire. Its not good enough for you to say that a document has "too many pages" and that "i have no idea how tests are carried out" and then go on to question the validity of certification systems.

Chris Arch

Not that I want to compete with you on this subject... But I have probably more education than you have...

When I buy some food I read the content and I assume that it describes what I eat. When I use a product I read the description and if I see the BBA cert No. or equivalent, I assume that it performs as described.

When Beyondpassive states that some insulation materials do not deliver the certified standard, what is he pretending?

The particular insulation that I am planning to use had its thermal conductivity tested as per BS EN 13165: 2001. Moisture resistance tested as per BS 5250: 2002 and so on.

This particular insulation received the British Board of Agreement Certificate for a U-Value as low as 0.16 while using a fully filled cavity of 100mm depending on the block lambda.

Beyond passive insinuates that the U-value is probably around 0.20 instead. Then my questions are: “do you pretend that the BBA carries out flawed testing?”, “Do you pretend that British Standards aren’t reliable to carry out these tests?”.

I am not putting in question the BBA or Irish equivalent as you insinuate, in the contrary I am fully relying on them. However today I am told that I should not… Then I am trying to understand the issue. I am not a thermal engineer or whatever these professionals are called and I am relying on certificates. You should understand that when someone tells me that those certs are flawed, I become curious.

I think that I have used plain English. Maybe you are passing through the subject without being able to catch it…

Either Beyondpassive assertions are correct and the BBA certificates and BS tests are not reliable, or the contrary…

If Beyongpassive is speaking about poor workmanship this is another story. I assume that the insulation is fitted as per manufacturer’s instruction to deliver certified performance.

muffler

beyondpassive wrote: »

The drafts were down to workmanship as there were gaps between the sheets where they lapped.

Chris Arch wrote: »

If Beyongpassive is speaking about poor workmanship this is another story.

Keep up at the rear please :rolleyes:

sinnerboy

Mod Warning to Chris Arch

Watch your tone here. this forum is good place to discuss and learn if you use it properly.

Tips

- if someone goes to the trouble of providing you with a detailed link please read it before dismissing it as having "too many pages"

- read carefully what others have posted. Beyondpassive did not suggest anything with regard to BBA certification he simply expressed his expectation.

- take sometime to reflect before posting again - or you will be given time in the form of a ban