Just started a self-build in Dorset. Exciting times!

[Carly Lawson]

Hi Thorfun, isn't MBC twinwall TF build really expensive and the walls very thick? Is that the system that puts SIPs in-between the timber frame? We also looked at SIPs made in Scotland. They gave us lots of information at the NEC show but to get a good insulation level the walls are really wide. We are looking for advice on the best system to use but timber doesn't seem to be as good or ecofriendly as the UK made woodcrete (similar to TF). On their website they have the insulation built in, so that seems a bit easier? Sorry, new to the forum and just trying to make the right decision.  

[Russell griffiths]

1 hour ago, Carly Lawson said:

Hi, that sounds like an amazing build.  We looked at Nudura but then we found out you have to use loads of bracing and extra bits, which is very expensive and not included in the price, we also worried that the render may not stay on. Plus we are trying to be as environmentally and sustainable. We found out that Nudura is imported all the way from America?  

We are still trying to decide which product to use for our self build. We looked through your post and we have also looked at Durisol/Ecobrix because you mentioned them. We did some research and thought that it looked like a better option as it's more straight forward no extra costs and UK made.

 

We saw them at them at the NEC show. They invited us to visit one of their builds and they gave some history about the product. We were amazed that Europe has more than 400,000 houses built with woodcrete and that its been around for so long. 
 

I think you need to do some more detailed research. 

some of your points mentioned here are ludicrous. 
 

very few things you build with will be made in England 

 

thinking something is expensive because it needs additional bracing to erect it is like saying timberframe is cheaper, but forgetting you need a crane to put it up. 
my bracing cost for my icf was around £1000 for a 240m build. 
Picking a product like durisol because it doesn’t require bracing is absolutely bonkers. 
 

look at the products in detail and then break the cost down versus the benefit. 

[Carly Lawson]

Hi, sorry I am new to the forum and did not mean to cause offence. I was just saying that we are trying to find an affordable way to build that is ecofriendly and use sustainable materials. We have been looking around and please correct me if I am wrong but it seems that Ecobrix (new owners of Durisol) is one of the few UK made ICF's?  I can't imagine how much extra pollution and extra carbon must be produced to import EPS foam from the United states. Is that not a crazy thing to do or is that just what everyone dose? 
Also, why would you want to spend another £1000 for bracing? Is it not better to buy UK made, support local jobs and save £1000 cause you don't need bracing? Any guidance is welcome, we have not decided yet but the price per square meter from lady that owns Ecobrix seems very good but maybe I am missing something? I

 

[Carly Lawson]

Hi Russell, if you add in the extra money for bracing and the additional concrete that goes into the core for the polystyrene ICF, is that not a lost more expensive? That must add about £10 extra per square meter? Also, I picked up one of the woodcrete blocks at the NEC show,  they were not very heavy,  what do you need a crane for? 

I have also just started to research thermal mass.  It seems a wonderful benefit you get with the Ecobrix ICF system (same as the Italian system). 
I have only researched online but it looks like you don't get that benefit from the American polystyrene/EPS ICF systems? The other ICF's seem to have it locked in between 2 layers of foam?  How do you make things the kitchen cabinets attach to the inside of the house? 

[JohnMo]

1 hour ago, Russell griffiths said:

bracing cost for my icf was around £1000 for a 240m build. 
Picking a product like durisol because it doesn’t require bracing is absolutely bonkers

Durisol costs nothing to brace, well 4 sheets of osb and some screws. Nothing wrong with durisol, our external walls took us 4 weeks, (70m x 3m tall) neither of us (2 off) had done or used ICF and neither of are builders.

 

48 minutes ago, Carly Lawson said:

correct me if I am wrong but it seems that Ecobrix (new owners of Durisol) is one of the few UK made ICF's?  I can't imagine how much extra pollution and extra carbon must be produced to import EPS foam from the United states. Is that not a crazy thing to do or is that just what everyone dose?

Yes from recycling mostly old end of life pallets, very little cement, made in Wales.

 

Easy for anyone to build from. Render and or plaster directly to the woodcrete. U value of 0.14 out the box, zero cold bridges, very little rebars required. You actually screw things to the woodcrete without issue. Lots of things to like.

Edited April 5 by JohnMo

[Carly Lawson]

Thank you, that's very kind and so good to know. They said they would give us the quantity for cement and rebar but we have to work that out.  It seems straight forward and made in Wales is amazing! My husband and I are hoping to do as much as possible to keep the costs down. Did you render the walls yourself?  

[SteamyTea]

59 minutes ago, Carly Lawson said:

I can't imagine how much extra pollution and extra carbon must be produced to import EPS foam from the United states.

The base crude oil it came from quite possibly was more local to where the foam was made, Gulf of Mexico, Texas, Canada, the USA is still the largest producer of crude oil, so makes sense to make products there.

If the foam was made in the Western USA, it could have been processed with lower carbon fuel sources, wind, solar and hydro.

Transport by rail and ships is the best way to reduce transport embodied energy and carbon in high volume products.  Not as if they pop the stuff in a plane.  The UK has very high transport energy costs as we move just about everything by relatively small trucks.

 

Ask @ToughButterCup about not bracing Durisol, and if you are really concerned about environmental damage, why are you not building a timber house?

You can look up the embodied energy and carbon for building materials on the University of Bath's website, Craig Jones is the man.

59 minutes ago, Carly Lawson said:

Is it not better to buy UK made, support local jobs

You need, if you want to be environmentally sound, pick products from the most productive factories, not the ones near by.  Productive factories are more efficient.

In Economics, it is called division of labour.  Let people that are good at something get on with it, those that are not good at something need to do something else.

Edited April 5 by SteamyTea

[JohnMo]

8 minutes ago, Carly Lawson said:

They said they would give us the quantity for cement and rebar but we have to work that out.

You need a structural engineer for the rebar calcs. Durisol had a really good build manual, you should be able to find it online.  

[JohnMo]

10 minutes ago, Carly Lawson said:

Did you render the walls yourself

No we didn't render at all, as I hate the stuff. I used stone slips and Scottish larch cladding.

 

Inside we did a lime, cement parge coat for airtightness, and sevice void for from battens screwed to durisol and the dry lined with plasterboard.

 

Doing it again I would miss the parge coat and use a smart air tight vapour barrier membrane, less mess and quicker.

[Carly Lawson]

Hi JohnMo, I think your house sounds amazing. Stone Slips must look amazing! Our architect was thinking mainly render with brick slips (hemp brick slips) to add some charm. However, maybe we should look at adding in some stone slips, ground level as a feature. Thank you so much.  This forum has so much helpful advice. 

I don't understand what steamytea is talking about, sorry that all seems very complicated and I have not been to the Ecobrix factory yet and I don't know anything about crude oil.  I just know that if we can, we'd would like to try and be ecofriendly and support UK business and jobs. This country was once full of shops and people had jobs making things but now it seems that people get angry if you try to suggest buying something made in Wales! I don't understand that. 

We do like the Timber frame but it seems we will save money and the walls will be thinner if we have ICF walls. We were impressed to learn that the ecobrix blocks are mostly made of recycled wood, so isn't that kinda the best of both worlds because we will have a timber roof and floors will all be made here in the UK.   

[JohnMo]

[Carly Lawson]

OMG OMG OMG that is magical!!! I absolutely love it!! Thank you for sharing. What a beautiful setting and design! Gosh, I hope we do something that good 

[SteamyTea]

3 minutes ago, Carly Lawson said:

we'd would like to try and be ecofriendly

You have to define what you mean by 'eco friendly'.

When I was at university doing my environmental science degree, most of the course was made up of ecologists, then there were 4 surf science students, one marine management student and 3 of us from the renewable energy course.

The surfers have had the biggest impact in cleaning up the environment.

[Carly Lawson]

Hi SteamyTea, I really appreciate all environmental efforts. We try to help where we can (not easy with work and kids) My husband and I have been privileged to spend some time volunteering with a group that is working to alleviate the damage from ghost fishing. It's so upsetting to see the damage done by discarded fishing nets. 
Thank you for the input.  I'll update the forum with our selfbuild adventure. Hopefully we will find the best materials to use.  We only get to do this once, and if we end up with something as beautiful as JohnMO's Ecobrix house, we will be over the moon!

[NailBiter]

The Nudura at least flat packs (folds down) and is reasonably light. It probably isn't as ecofriendly as a mineralised wood product like Durisol or Ecobrix but a large part of the "issue" with ICF houses is going to be the concrete itself.

We got a quote from MBC for the ground floor and 1st floor (lower ground is below grade so would have been ICF in either case) and it was high. I've not had the full comparative quote for ICF through yet as we have had to do additional ground surveys (now complete!) and redesign the lower ground floor.

I will post a comparison once I have the data.

Edited April 5 by NailBiter

[SteamyTea]

36 minutes ago, Carly Lawson said:

Hopefully we will find the best materials to use.

No hope needed.

Download a copy of ICE from here.

https://circularecology.com/embodied-carbon-footprint-database.html

 

It can quickly show which are the better materials environmentally.

[Thorfun]

4 hours ago, Carly Lawson said:

Hi Thorfun, isn't MBC twinwall TF build really expensive and the walls very thick? Is that the system that puts SIPs in-between the timber frame? We also looked at SIPs made in Scotland. They gave us lots of information at the NEC show but to get a good insulation level the walls are really wide. We are looking for advice on the best system to use but timber doesn't seem to be as good or ecofriendly as the UK made woodcrete (similar to TF). On their website they have the insulation built in, so that seems a bit easier? Sorry, new to the forum and just trying to make the right decision.  

the quote we got wasn't cheap but you get what you pay for I guess. in the end we decided to just use a standard TF and fitted the insulation ourselves to save money. it took well over a year to do it all and was horrible work. if I was to do another self-build I would get the TF company to install the insulation. I keep thinking that if I'd spent the extra money we'd be living in the house by now enjoying it. and we'd be off our self-build mortgage and I wonder if the extra payments on that have amounted to more than we saved fitting the insulation ourselves? sometimes a saving isn't really a saving when you consider the time and other costs involved.

 

the MBC twin wall system is 300mm thick walls. I thought they were thick when I first started looking at it but our standard TF 140mm walls with 80mm internal insulation means that our walls are only 80mm thinner which is nothing in the grand scheme of things.

 

I don't understand what you have against thick walls though. 

[Carly Lawson]

Thank you Steamytea for the link to ICE.  That looks like a good reference point.

[Russell griffiths]

@Carly Lawson there’s nothing to apologise for, I just think you are jumping to decisions after talking to someone selling a product. 
 

it’s like the saying, don’t ask a barber if you need a haircut. 
 

I would say do more research, and then base your answers on sound evidence. 
 

you have mentioned wall thickness a couple of times, unless your land is only a few metres wide then 50mm wider or thinner is not going to matter. 
 

the crane comment was in regards to a timberframe house, like saying timberframe was cheaper, but forgetting you needed a crane to put it up. 
 

I think we’re hijacking the original post here, so maybe start your one about your journey and hopefully we can point you in the right direction there. 

[joe90]

Choosing build method is not easy, luckily there are examples of all sorts here from people that have done it, not selling it. I went from straw bail build to brick and block. Were I to do it again I would probably go timber frame and cellulose blown insulation. I have been impressed with MBC from what has been said here. Good for you for trying to using local companies and products.

[JohnMo]

12 hours ago, Russell griffiths said:

you have mentioned wall thickness a couple of times

That is a good point, irrespective of build method used if you want decent insulation values in the walls, (any build method) they will be quite thick. My durisol walls are not thin, at the front (cladding external and battens/plasterboard inside) are about 600mm thick, rear (stone slips) 500mm thick.

[MikeSharp01]

54 minutes ago, JohnMo said:

That is a good point, irrespective of build method used if you want decent insulation values in the walls, (any build method) they will be quite thick

We went for Stick built with 300mm I beams, filled with blown cellulose, and added a thin layer of PU on the outside which meant we got our target U value with a small amount of oil based product and a bit thinner. So far this winter without heating it has never dropped below 8 deg C and we still don't have the outer cladding on some of the walls and none of the plaster board inside both of which will further improve it. So our total thickness when all done is 460mm. 

[Carly Lawson]

Afternoon, Thank you for the additional information.  Yes, the plot we bought has limited space either side.  However,  we have plenty of space front and back. So we are looking at adding some features to the front and rear.

Due to the space limitations our architect see's the Ecobrix wall as a total of 440mm. 20mm render, 365mm block 40mm gap and 15mm plasterboard. 

At the weekend after reading the above, I researched using the CHATGPT AI to compare the different types of ICF. It all got a bit technical but the bullet points were that Nadura and other EPS ICF's works out to be more expensive than Ecobrix because the Durisol blocks use less cement and do not need bracing. There are a few reasons for this but one interesting point was that the inside dose not need to be battened (dab and dob or direct to the blocks). Seems that all the Styrofoam type ICF's need to be battened on the inside and the external needs different types of battens or boards fitted depending on what you want on the outside. With all the extras you need to build with EPS ICF it appears to add something like £17 or maybe even £23 per square meter. Plus the additional carbon from international transport. 

 

We are only looking to have render and brick slips (Maybe some stone slips). Apparently these fix straight on to the rough surface of the woodcrete.

It also looks like the Ecobrix is more breathable. The AI pulled a lost of information about condensation and it seems that there is a lot of data available on woodcrete (loads of university research papers) and the inside of woodcrete and also hempcrete homes are much healthier to live in. The ChatGPT also added that Products like SIPS preformed even lower for breathability than version of ICF (Interesting!) 

 

The last point that the AI delved into was the thermal mass. The main point was that the EPS/Styrofoam ICF did not provide the same benefit as the thermal mass from the woodcrete blocks.  It basically said that because the concrete core was sandwiched between 2 layers of EPS foam,  any thermal mass benefit would be lost. However,  the Canadian, European and British woodcrete blocks are all designed to give maximum benefit of the thermal mass.  It seems that over the life of the building,  there is significant energy savings because the thermal mass helps regulate the heating and cooling of the building (warm in winter/cool in summer). 

 

In summery,  it seems that according to the AI, Nailbiters first woodcrete choice would have worked out more environmentally friendly and less expensive and that makes JohnMo and Russell Griffiths, builds even more amazing!  

 

Sorry for the long reply, I will start a new thread now that I underhand the forum and the information. 

[JohnMo]

23 minutes ago, Carly Lawson said:

breathable

Can have benefits and also pit falls. Breathable from a moisture perspective in is good, breathable from air exchange perspective is not so good as it drives up energy costs. 

[NailBiter]

You should however be aware of the limitations of an LLM (large language model) such as ChatGPT before making too many decisions based upon what it says.

For example here is a case of a lawyer getting in trouble because he relied on ChatGPT which fabricated court cases that never happened:

https://www.theverge.com/2023/5/27/23739913/chatgpt-ai-lawsuit-avianca-airlines-chatbot-research

 

Quote

The opposing counsel made the court aware of the issue in painful detail as it recounted how the Levidow, Levidow & Oberman lawyers’ submission was a brief full of lies. In one example, a nonexistent case called Varghese v. China Southern Airlines Co., Ltd., the chatbot appeared to reference another real case, Zicherman v. Korean Air Lines Co., Ltd., but got the date (and other details) wrong, saying it was decided 12 years after its original 1996 decision.
 

Schwartz says he was “unaware of the possibility that its content could be false.” He now “greatly regrets having utilized generative artificial intelligence to supplement the legal research performed herein and will never do so in the future without absolute verification of its authenticity.”

 

Quote

This once again highlights the absurdity of using chatbots for research without double (or triple) checking their sources somewhere else.

Microsoft’s Bing debut is now infamously associated with bald-faced lies, gaslighting, and emotional manipulation. Bard, Google’s AI chatbot, made up a fact about the James Webb Space Telescope in its first demo. Bing even lied about Bard being shut down in a hilariously catty example from this past March
.

Being great at mimicking the patterns of written language to maintain an air of unwavering confidence isn’t worth much if you can’t even figure out how many times the letter ‘e’ shows up in ketchup.

 

Edited April 8 by NailBiter