Extension - are we dreaming?

Handsandtools · 13-08-2017 7:34pm

You have to choose thermal block with highest thermal resistance say 6.94 and that will give you U-value of 0.14, taking into account that u-value is not constant and there's 5% thermal bridging, you will get U-value around 0.16 and will comply with part L easy.

sydthebeat · 14-08-2017 12:40pm

Handsandtools wrote: »

Floor structure stay same if you go for UFH it does not mean you have to change whole floor structure especially if you go for electric floor heating option. If you use easy flow screed than it is a bit different.
Thermal blocks is used in Ireland exceptionally to reduce thermal bridge, but in UK and rest of the world they are used to reduce or completely replace insulation.
500mm block will have u-value of 0.11-0.16 well in Passive house requirement.

floor structure does not stay the same if you decide down the line to switch between a rad system to an UFH system,...

standard rad system has pipes lagged within a 100 - 150 concrete floor slab, on 100mm insulation (current regs min)

UFH will have the UFH system within a typically 75mm concrete screen on 125-150mm insluation (min u value 0.15 to be achieve) on a typically 100-150 concrete sub floor.

if you use an easi screed system the thickness of the screed is reduced even further.

you cannot switch from one system to the other without major repercussions.

on thermal blocks, there is no 500mm thermal block out there which will give you anything close to a 0.11 u value
Poroton T8s (425mm wide) will only get you to 0.18 without extra insulation applied.
0.18 wall u value will lead to uneconomical specifications for other elements of construction to be in any way a viable specification.

irish building regs are too onerous for these single leaf thermal blocks to be a viable alternative for a new build house..

Calahonda52 · 14-08-2017 8:31pm

Handsandtools wrote: »

..
Thermal blocks is used in Ireland exceptionally to reduce thermal bridge, but in UK and rest of the world they are used to reduce or completely replace insulation.
500mm block will have u-value of 0.11-0.16 well in Passive house requirement.

Link please

Dudda · 15-08-2017 10:08am

sydthebeat wrote: »

floor structure does not stay the same if you decide down the line to switch between a rad system to an UFH system,...

standard rad system has pipes lagged within a 100 - 150 concrete floor slab, on 100mm insulation (current regs min)

UFH will have the UFH system within a typically 75mm concrete screen on 125-150mm insluation (min u value 0.15 to be achieve) on a typically 100-150 concrete sub floor.

if you use an easi screed system the thickness of the screed is reduced even further.

you cannot switch from one system to the other without major repercussions.

If you have 150mm insulation (or even more if you're going the EPS route due to current shortage of PIR) with a concrete slab depth to engineers spec then you can have both rads or underfloor insulation.
A lot of people now zip tie underfloor heating pipes to the top layer of steel mesh in the floor slab with the insulation below. This means you don't need a screed or easi screed for the UFH pipes. It's standard for all passive house insulated foundation slabs with underfloor heating.

I agree with your other points on the thermal blocks.

Poor Uncle Tom · 15-08-2017 10:21am

Dudda wrote: »

If you have 150mm insulation (or even more if you're going the EPS route due to current shortage of PIR) with a concrete slab depth to engineers spec then you can have both rads or underfloor insulation.
A lot of people now zip tie underfloor heating pipes to the top layer of steel mesh in the floor slab with the insulation below. This means you don't need a screed or easi screed for the UFH pipes. It's standard for all passive house insulated foundation slabs with underfloor heating.

I agree with your other points on the thermal blocks.

Why would you put the UFH pipes within the floor slab (approx 150mm thick slab) doesn't that make the UFH very ineffective, very slow to react to changes, slow to heat that mass of concrete up and slow to cool that mass also.

That's the reason for putting the UFH pipes in a separate screed in the first place.

sydthebeat · 15-08-2017 11:04am

Dudda wrote: »

If you have 150mm insulation (or even more if you're going the EPS route due to current shortage of PIR) with a concrete slab depth to engineers spec then you can have both rads or underfloor insulation.
A lot of people now zip tie underfloor heating pipes to the top layer of steel mesh in the floor slab with the insulation below. This means you don't need a screed or easi screed for the UFH pipes. It's standard for all passive house insulated foundation slabs with underfloor heating.

I agree with your other points on the thermal blocks.

lets be clear im not talking about passive designed and specified houses because they are not the standard build here (yet)

also, i was referring to a decision down the line to change from a rad system to an UFH system ... as not being at all easy or cheap.

first off he standard spec currently for a rad system is lagged pipes within a 150mm floor slab on 100 PIR insulation.
If you want to change this to UFH the only cheap method is to lay UFH over the floor slab and pour an easy screed type.
so youd end up with UFH within a 200 storage element on 100 insulation.... a resolution that would be very unresponsive, expensive to run and difficult to control.

it simply is not at all easy to alternate from a rad system to an UFH system, or vice versa.... without actually installing both systems initially...and forgoing economies on which ever one you want to use.

Handsandtools · 15-08-2017 10:06pm

sydthebeat wrote: »

floor structure does not stay the same if you decide down the line to switch between a rad system to an UFH system,...

standard rad system has pipes lagged within a 100 - 150 concrete floor slab, on 100mm insulation (current regs min)

UFH will have the UFH system within a typically 75mm concrete screen on 125-150mm insluation (min u value 0.15 to be achieve) on a typically 100-150 concrete sub floor.

if you use an easi screed system the thickness of the screed is reduced even further.

you cannot switch from one system to the other without major repercussions.

on thermal blocks, there is no 500mm thermal block out there which will give you anything close to a 0.11 u value
Poroton T8s (425mm wide) will only get you to 0.18 without extra insulation applied.
0.18 wall u value will lead to uneconomical specifications for other elements of construction to be in any way a viable specification.

irish building regs are too onerous for these single leaf thermal blocks to be a viable alternative for a new build house..

If you look closely and dig deeper you will find better solutions. 100-150 mm subfloor not for all systems, if you install insulation 150mm tick and 70-100mm concrete screed, you still can use electric floor heating system .

Talking about blocks you are not informed well:
https://bauroc.eu/uploads/2017/06/bauroc_product_catalogue.pdf
Bauroc ecoterm+

Handsandtools · 15-08-2017 10:07pm

Calahonda52 wrote: »

Link please

https://bauroc.eu/uploads/2017/06/bauroc_product_catalogue.pdf

Handsandtools · 15-08-2017 10:12pm

sydthebeat wrote: »

lets be clear im not talking about passive designed and specified houses because they are not the standard build here (yet)

also, i was referring to a decision down the line to change from a rad system to an UFH system ... as not being at all easy or cheap.

first off he standard spec currently for a rad system is lagged pipes within a 150mm floor slab on 100 PIR insulation.
If you want to change this to UFH the only cheap method is to lay UFH over the floor slab and pour an easy screed type.
so youd end up with UFH within a 200 storage element on 100 insulation.... a resolution that would be very unresponsive, expensive to run and difficult to control.

it simply is not at all easy to alternate from a rad system to an UFH system, or vice versa.... without actually installing both systems initially...and forgoing economies on which ever one you want to use.

There's an overlay option for UFH, and regarding 150mm , it can be 100-150mm depending on design. Talking about efficiency, the bigger the slab the more thermal mass.
Regarding blocks, you are way under-informed.

Handsandtools · 15-08-2017 10:14pm

Discussion started about insulation, why you choose to put 70mm instead of 140 if required minimum is 100 mm, and more insulation mean less heat loss.

sydthebeat · 15-08-2017 11:08pm

You do realise the minimum standard compressive strength of a block is 7.5n/mm2 since 2013????

That block you've linked to has a strength of 1.8.... About 25% of what's required.

You may as well be building with candy floss.

Handsandtools · 15-08-2017 11:20pm

sydthebeat wrote: »

You do realise the minimum standard compressive strength of a block is 7.5n/mm2 since 2013????

That block you've linked to has a strength of 1.8.... About 25% of what's required.

You may as well be building with candy floss.

If you mix I.S. EN 771-1 with I.S. EN 771-4 ???
I can send you copy of EN 771-4 and look for your self.
771-1 is nothing to do with Autoclave Aerated concrete, another half study example.

Construction Products Directive

Structural construction products constitute an important part of the construction products market. The link between the Eurocodes and the Construction Products Directive is twofold.

In some cases, the declared values, as required by the harmonised standards, serve as inputs to the Eurocodes. For example, the compressive strength of a masonry block as defined by I.S. EN 771 is required as an input for designing to the Masonry Design Eurocode I.S. EN 1996.

In other cases, the harmonised technical specifications for certain products and systems involve structural design in arriving at the declared properties of the products. Eurocodes will provide the basis for design of such components, for example timber Frame or Concrete Frame Building Kits, Metal Frame Building Kits, structural metallic products and ancillaries such as trusses, metal framing, stairs, thus becoming a driver for further innovation in the industry.

In both cases, the Eurocodes should be the basis for assessing or the protocol for declaring the mechanical strength of structural construction products in the development of harmonised technical specifications under the Construction Products Directive.

Poor Uncle Tom · 16-08-2017 9:18am

Handsandtools wrote: »

If you mix I.S. EN 771-1 with I.S. EN 771-4 ???
I can send you copy of EN 771-4 and look for your self.
771-1 is nothing to do with Autoclave Aerated concrete, another half study example.

Construction Products Directive

Structural construction products constitute an important part of the construction products market. The link between the Eurocodes and the Construction Products Directive is twofold.

In some cases, the declared values, as required by the harmonised standards, serve as inputs to the Eurocodes. For example, the compressive strength of a masonry block as defined by I.S. EN 771 is required as an input for designing to the Masonry Design Eurocode I.S. EN 1996.

In other cases, the harmonised technical specifications for certain products and systems involve structural design in arriving at the declared properties of the products. Eurocodes will provide the basis for design of such components, for example timber Frame or Concrete Frame Building Kits, Metal Frame Building Kits, structural metallic products and ancillaries such as trusses, metal framing, stairs, thus becoming a driver for further innovation in the industry.

In both cases, the Eurocodes should be the basis for assessing or the protocol for declaring the mechanical strength of structural construction products in the development of harmonised technical specifications under the Construction Products Directive.

Weakest argument I have ever seen for non compliance with Building Regulations.

Handsandtools · 16-08-2017 11:06pm

Poor Uncle Tom wrote: »

Weakest argument I have ever seen for non compliance with Building Regulations.

Non compliance? I think you want compare elephant with horse. AAC blocks comply with building material requirements for AAC products I.S. EN 771-4 but you want them to comply with concrete building product requirements I.S. EN 771-1. Only a lazy ''engineer'' or ''architect'' can pull all materials under one requirement, but what to expect, when concrete industry in Ireland can't employ a proper geologist to explain what Pyrite is.
Did timber frame have to comply with same rule???
Guys, I will encourage you to study.

sydthebeat · 17-08-2017 10:26am

Handsandtools wrote: »

Non compliance? I think you want compare elephant with horse. AAC blocks comply with building material requirements for AAC products I.S. EN 771-4 but you want them to comply with concrete building product requirements I.S. EN 771-1. Only a lazy ''engineer'' or ''architect'' can pull all materials under one requirement, but what to expect, when concrete industry in Ireland can't employ a proper geologist to explain what Pyrite is.
Did timber frame have to comply with same rule???
Guys, I will encourage you to study.

Not correct

no one is questioning the compliance of AAC blocks with IS EN 771-4 2011

what we are questioning is the use of a 1.8 N/mm2 block in a structurally loaded wall as being in compliance with TGD A "structure".

In the Uk the minimum compressive strength allowed in even the smallest single storey situation is 2.9 n/mm2... and a 2 storey section requires 7.3 n/mm2.... which is very similar to our own 7.5n/mm2 requirement here.

the only situation i can your blocks as being building regulation compliant is as a non structural in-fill wall within a larger framing structure.

and yes, a timber frame external block leaf also needs to comply with 771-3

to be honest, ive seen new products come into ireland and be heralded as the the solution to end all solutions... only to be shown to be problematic and error ridden.
Ytong blocks, poroton, ICF, prefab insulated concrete, single leaf SIPs, etc etc
So i hope youll forgive me for being wary and unconvinced.

Handsandtools · 17-08-2017 3:56pm

sydthebeat wrote: »

Not correct

no one is questioning the compliance of AAC blocks with IS EN 771-4 2011

what we are questioning is the use of a 1.8 N/mm2 block in a structurally loaded wall as being in compliance with TGD A "structure".

In the Uk the minimum compressive strength allowed in even the smallest single storey situation is 2.9 n/mm2... and a 2 storey section requires 7.3 n/mm2.... which is very similar to our own 7.5n/mm2 requirement here.

the only situation i can your blocks as being building regulation compliant is as a non structural in-fill wall within a larger framing structure.

and yes, a timber frame external block leaf also needs to comply with 771-3

to be honest, ive seen new products come into ireland and be heralded as the the solution to end all solutions... only to be shown to be problematic and error ridden.
Ytong blocks, poroton, ICF, prefab insulated concrete, single leaf SIPs, etc etc
So i hope youll forgive me for being wary and unconvinced.

I'm getting your point, but TGD are guidance document, that means, if I'm not qualified to calculate or understand structure, I follow TGD. TGD are based on old type of buildings, the ones were built till 1960's in Europe.
When I meant timber frame I meant timber frame not hybrid timber and concrete block as if you use concrete block it must comply I.S EN 771-3, but if you use AAC than you must comply 771-4 but not 3
I don't see any problem in UK with AAC blocks and if you read true I.S. EN 771-4 than you find that minimum requirement for AAC is 1.1n/mm2
Never seen any building, built with AAC in Scandinavia to be problematic even with heavy snow loads and stormy conditions,and they are used as load bearing structure. They are way stronger than hollow blocks used here as support area of those are tiny.
Problem is, everyone is looking for less responsibility and keep using one system and that's it, but you can't build light-bulb with candle, so it is getting very expensive and inefficient to build in Ireland as no new methods are accepted.
I will suggest a trip to northern counties to look and see how people live there in colder conditions with more efficient building technologies.

sydthebeat · 17-08-2017 5:24pm

Handsandtools wrote: »

...
Problem is, everyone is looking for less responsibility ......

i certainly agree with this point, but id flesh it out by saying our building control system of self certification creates an industry of very defensive specification.

the problem i see with your argument is that you are using the European Norm as the standard to meet when, our own technical guidance documents, which are prima facia compliance requires a stated compressive strength of 7.5N/mm2 when tested in accordance with EN 772

you need to show that your 1.8 N/mm2 AAC block is comparable in strength and thickness to a solid masonry block of 7.5 N/mm2.

if you can do that... fair dues.

Handsandtools · 18-08-2017 11:05am

sydthebeat wrote: »

i certainly agree with this point, but id flesh it out by saying our building control system of self certification creates an industry of very defensive specification.

the problem i see with your argument is that you are using the European Norm as the standard to meet when, our own technical guidance documents, which are prima facia compliance requires a stated compressive strength of 7.5N/mm2 when tested in accordance with EN 772

you need to show that your 1.8 N/mm2 AAC block is comparable in strength and thickness to a solid masonry block of 7.5 N/mm2.

if you can do that... fair dues.

Totally agree on "defencive"!
But what I'm saying is that based on EN 7.5N/mm2 is required only for dense building blocks not for AAC blocks and similar. But TGD used only requirement for dense blocks and applied to all materials used. If you build from lighter material you have less pressure on the structure, apart from that material surface area must be larger but all that can be found in EN. If TGD will use the right approach then each different material have there separate requirement as it is with EN 771-1;771-2;771-3;771-4 etc.
http://v5.books.elsevier.com/bookscat/samples/9780750669405/9780750669405.pdf

Good read about differences.

sydthebeat · 18-08-2017 1:36pm

Handsandtools wrote: »

Totally agree on "defencive"!
But what I'm saying is that based on EN 7.5N/mm2 is required only for dense building blocks not for AAC blocks and similar. But TGD used only requirement for dense blocks and applied to all materials used. If you build from lighter material you have less pressure on the structure, apart from that material surface area must be larger but all that can be found in EN. If TGD will use the right approach then each different material have there separate requirement as it is with EN 771-1;771-2;771-3;771-4 etc.
http://v5.books.elsevier.com/bookscat/samples/9780750669405/9780750669405.pdf

Good read about differences.

i know the differences between types of blocks.
im talking about situations in which those blocks can / should be used.

in the UK the comparable regulations SPECIFICALLY refer to the allowed compressive strength of AAC blocks.

see table 6 and diagram 10 here

now, our own regs are not as prescribed , but i see no reason as to why youd disregard their requirements.
In most 2 storey cases condition B would occur therefore their regulations prescribe that a min compressive strength of 7.3N/mm2 is required when using AAC blocks.

Handsandtools · 18-08-2017 2:19pm

sydthebeat wrote: »

i know the differences between types of blocks.
im talking about situations in which those blocks can / should be used.

in the UK the comparable regulations SPECIFICALLY refer to the allowed compressive strength of AAC blocks.

see table 6 and diagram 10 here

now, our own regs are not as prescribed , but i see no reason as to why youd disregard their requirements.
In most 2 storey cases condition B would occur therefore their regulations prescribe that a min compressive strength of 7.3N/mm2 is required when using AAC blocks.

Condition B will only occur in higher buildings, and these calculations are based on cavity wall as you can see the minimum thickness there is way less than 1.8n/mm2 blocks 375mm and 500mm. the thinner the wall the stronger material must be used.
I just think there's to many lazy ''specialists'' and in order to calculate and test materials, they just go for the biggest number.
There's a lot of proofs of that:
1)mineral wool insulation use in cavity walls (any respectable tradesman will know that this it wrong)
2)PIR insulation used externally (everyone in Europe knows that PIR is not suitable for external insulation especially on high rise buildings),
3) Pyrite - when you study civil engineering or to become a foreman, you must study geology and the way building materials are made. So in the schools you learn about different minerals. But in Ireland, some "professionals" are allowed to make fortune by selling products "called" building blocks without testing ingredients and what's worse, in whole industry there was no one who can say that this metal looking mineral in the quarry is Pyrite and not suitable for manufacturing building blocks

There's more stories like this, but these are the most popular.
And now tell me that these BS and TGD guys are better and smarter than people behind EN771, our whole European civil engineers, who chose to use innovative materials and deliver 1000s of houses around the world using these materials?

I see a lot of wrong doing in construction industry and most of it is lack of knowledge, greed and lazy people.

Goldengirl · 13-09-2017 1:46pm

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kkelliher · 15-09-2017 10:32pm

Goldengirl wrote: »

This post has been deleted.

Over the last 15 years we have completed cost plans for clients on their plans for extensions, new build, refurbs and without doubt 99% of these ended up well in excess of the clients budget. I don't agree that there is a bubble in the extension market, the reality is there is a shortage of labour and therefore costs are rising but this is a simple supply and demand issue and not a bubble. A bubble implies there are massive profits/price inflation etc and this is simply not the case in the general extension and refurb market where there is still very much a race to the bottom in the tender market. It has always been expensive to build and will always be and many many people will simply not afford to do it and that is a simple but unfortunate reality.

scwazrh · 15-09-2017 10:37pm

Goldengirl wrote: »

This post has been deleted.

Do you mean that you are building a two storey extension , total floor space of 68sqm or a single storey , ground floor only of 34sqm?

Goldengirl · 15-09-2017 11:27pm

This post has been deleted.

BryanF · 15-09-2017 11:47pm

kkelliher wrote: »

Over the last 15 years we have completed cost plans for clients on their plans for extensions, new build, refurbs and without doubt 99% of these ended up well in excess of the clients budget. I don't agree that there is a bubble in the extension market, the reality is there is a shortage of labour and therefore costs are rising but this is a simple supply and demand issue and not a bubble. A bubble implies there are massive profits/price inflation etc and this is simply not the case in the general extension and refurb market where there is still very much a race to the bottom in the tender market. It has always been expensive to build and will always be and many many people will simply not afford to do it and that is a simple but unfortunate reality.

+1

well said

BryanF · 15-09-2017 11:50pm

Goldengirl wrote: »

This post has been deleted.

Look apologies for being flippant but, follow on from KK's post,
Please show us how / where m2 costs have any relevance anywhere ever

Goldengirl · 16-09-2017 12:59am

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DOCARCH · 16-09-2017 7:38am

Goldengirl wrote: »

This post has been deleted.

There are enough caveats in past posts not to rely on per/m.sq. ballpark rates. Just use them for general guidance.

Even during the downturn I was doing extensions where some worked out at E 1,200/m.sq. and some worked out in excess of E 3,000/m.sq.

The problem with any extension is it all depends....

Size (in terms of economies of scale), complexity, works required to the existing house, work near/on boundaries, site access, etc., etc.

There is no bubble at the moment. As stated above, just a shortage of supply. Main contractors are not making huge profits....they are just being charged more for materials, and, being charged more by their sub-contractors (electricians, plumbers, etc.).

Goldengirl · 16-09-2017 12:49pm

This post has been deleted.

davidblake · 17-09-2017 7:36pm

Just bought a 3 bed house in Clare. We will need to add an extension with a bedroom downstairs but was thinking of a 2 story extension with a laundry upstairs. Does anyone have an idea of roughly what this would cost?

The house is a 3 bed semi detached and we woulld have room at the side to do it

Extension - are we dreaming?

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