Porotherm bricks

vendredi

Hi knowledgeable members.

I have been using the board looking for information as we are going to build this year. Here's time for me to pick the collective brain.

I am looking at Porotherm bricks as the main building material, insulation on the outside and plasterboard / skim on the inside.

Would anyone consider this a valuable alternative to a factory made timber frame (purely in terms of efficiency)?

Thank you

BryanF

vendredi wrote: »

Hi knowledgeable members.

I have been using the board looking for information as we are going to build this year. Here's time for me to pick the collective brain.

I am looking at Porotherm bricks as the main building material, insulation on the outside and plasterboard / skim on the inside.

Would anyone consider this a valuable alternative to a factory made timber frame (purely in terms of efficiency

Thank you

can you elobrate on what you mean by efficiency? cost, energy or speed of assembly etc..
porotherm are a viable option used extensively across the EU, the 44 block gives circa .2kw/m2
its a breathable product but its success will depend on what insulation and render you put outside of it.
plus its terracotta (clay) so comparison to concrete blocks its a lower production of CO2

not sure how they compare on price with timber frame.. i think theres more to considered than a msq difference - such as time to erect, labour, skills etc

vendredi

Defining efficiency has been the bane of my decision making.

Trying to make it simple I am aiming for A3 rating (even though I understand that BER can have little relation with energy performance)
My build is for a bungalow with loft so structurally it seems better to have solid rather than timber.

All 3 methods (block / timber / clay) can be built to meet the regulations
timber / clay are more sustainable than block
clay is healthier than the other 2
I am waiting for a couple of quotes to confirm but it looks like for the same results, the price difference between clay and timber may not be too high.
Factory built timber is precisely assembled so less room for imperfections.
Timewise, timber and clay would be faster than blocks.

If anyone had experience building or leaving in clay house, I would appreciate info.

So I am undecided between timber and clay. Price might be the decider.

BryanF

vendredi wrote: »

Defining efficiency has been the bane of my decision making.

that's why you employ a professional, thats why we get paid the big bucks

Trying to make it simple I am aiming for A3 rating (even though I understand that BER can have little relation with energy performance)

an A3 is the minimum requirement under the part L 2011 building regulations, although not stated, when you do your provisional BER that's what will be required. yes the BER has its flaws, and id recommend everyone do a phpp (passive house calculation) prior to submitting planning permission

My build is for a bungalow with loft so structurally it seems better to have solid rather than timber.

says who?

All 3 methods (block / timber / clay) can be built to meet the regulations
timber / clay are more sustainable than block
clay is healthier than the other 2
I am waiting for a couple of quotes to confirm but it looks like for the same results, the price difference between clay and timber may not be too high.
Factory built timber is precisely assembled so less room for imperfections.
Timewise, timber and clay would are faster than blocks.

So I am undecided between timber and clay. Price might be the decider.

I look forward to seeing your comparison

vendredi

BryanF wrote: »

that's why you employ a professional, thats why we get paid the big bucks

I have one on board. Big bucks all right, but the decision is still mine .

BryanF wrote: »

an A3 is the minimum requirement under the part L 2011 building regulations, although not stated, when you do your provisional BER that's what will be required. yes the BER has its flaws, and id recommend everyone do a phpp (passive house calculation) prior to submitting planning permission

Hence me not desperate to go higher than minimum regulation requirement but keen on best performance / budget.

BryanF wrote: »

says who?

ok, better maybe not better, but the load bearing capacity of clay blocks will not require as much structural add ons as load bearing of timber frame. In my case, it might affect the final look.

BryanF wrote: »

I look forward to seeing your comparison

I'll keep you posted. Have you any view you would like to share on either timber or clay?

BryanF

i suppose which ever is produced locally / has the lowest embodied energy. the whole wall build-up must be looked at from this perspective and health (natural and breathable). what insulation and weatherproofing material does your expense professional;) proposed to use with the poroton blocks and the same for the timber frame..

vendredi

BryanF wrote: »

i suppose which ever is produced locally / has the lowest embodied energy.

Either timber or clay are imported (from the companies I am dealing with so far)

BryanF wrote: »

the whole wall build-up must be looked at from this perspective and health (natural and breathable). what insulation and weatherproofing material does your expense professional proposed to use with the poroton blocks and the same for the timber frame..

Proposed by companies. I m taking those to the professional tomorrow.

Timber: 200mm cellulose external + Air tight membrane.
Clay bricks: 200 external EPS + Air tightness TBD.

BryanF

vendredi wrote: »

Either timber or clay are imported (from the companies I am dealing with so far)



Proposed by companies. I m taking those to the professional tomorrow.

Timber: 200mm cellulose external + Air tight membrane.
Clay bricks: 200 external EPS + Air tightness TBD.

U-value for each wall build-up?

muffler

Moved to C & P

vendredi

BryanF wrote: »

U-value for each wall build-up?

Timber: 0.18
clay: 0.136

BryanF

vendredi wrote: »

Timber: 0.18
clay: 0.136

should you not get a like with like u-value v cost comparison? ie 0.14 for the timber also?
as your installing 200mm eps outside the poroton then its probably lost its breathable properties and as the timber is insulated with cellulose, (without seeing any EE/CO2 figures) its looking like the sustainable winner...

vendredi

For a 0.14 U-Value: timber structure is quoted at 70k for a 173 sqm build.
Awaiting quote for equivalent U-Value with clay.

Do you have experience with clay blocks and their performance?

BryanF

vendredi wrote: »

For a 0.14 U-Value: timber structure is quoted at 70k for a 173 sqm build.
Awaiting quote for equivalent U-Value with clay.

Do you have experience with clay blocks and their performance?

specified a small extension with them, didn't have any problem, this was back when an Irish company (from I believe Wexford) was on hand for demonstrations etc. client went for mineral wool and timber cladding on battens externally to retain breathable structure. the only thing i can see where you may have a problem is getting guys trained up to use them, and maybe paying the engineer a little more for structure supervision, if the guys are not confident/competent. (but the same could be said for wider cavity and the level of attention required for low thermal brdiging detailing in block!)

vendredi

Thank you. I'll enquire about mineral wool. Part of the building is timber clad, the rest would have to be a breathable render.
Would you recommend a airtight membrane as well or is it overkill?

BryanF

vendredi wrote: »

Thank you. I'll enquire about mineral wool. Part of the building is timber clad, the rest would have to be a breathable render.
Would you recommend a airtight membrane as well or is it overkill?

i would say its the same as block - if you plaster every inch of the internal wall you should not need a membrane but its where sockets/services are cut out and attention is not paid to plastering that problems occur, (details at windows and joists etc membrane and tape will be required) but i think its about time you sat down with your architect.. there's a much bigger question going on here and thats what standard of building your aspiring too..

vendredi

Agree about the bigger question, which is why i started the thread. My architect has been very informative for timber and blocks so far but doesn't know much about the clay blocks, so I'm trying to get as much information outside of the potential provider so that we can make an informed decision, which we will do soon.
Thanks for following it.