'Passive slabs' - can anyone help?

[Mark Greenfield]

We (my wife and I) like the idea of a passive foundation slab, but can't find a company that will help design, supply and do all the work. We can source the materials from Ireland, but I'm worried about getting something wrong that will slow the build and cost us more money! Ideally, I'm looking for a company to do it all for us, and we take over from there (with a timber frame).

Build-Lite is the product we have seen - but they only supply. Surely there are others? We can't seem to find any though.

 

We had a similar scenario with screw piles, but that's another story - just odd there isn't a bit more 'joined-up thinking' for these things.

[Russell griffiths]

MBC timberframe will do the slab and frame. 
 

[IanR]

Advanced Foundation Technology Ltd. would be my first choice, but it's worth doing some searching on this site.... lots of options.

 

AFT and Wilkinson Passiv Homes do a number of projects together.

 

 

Edited May 28 by IanR

[garrymartin]

Here's the list from my Foundations "note" in my PKM system.

* MBC Passive Foundation, which is based on the patented Viking House Passive Slab
* Kingspan Aeroground, which is based on the Swedish Supergrund system
* Kore Insulated Foundation
* Castleform Raft Therm
* Isoquick
* AFT Passive Building Foundations
* Greenraft Insulated Raft

  
KORE: https://www.kore-system.com/

CASTLE FORMS: https://www.castleforms.com/

GREEN RAFT: https://www.greenraft.co.uk/

MBC TIMBER FRAME: https://www.mbctimberframe.co.uk/

VIKING HOUSE: http://www.viking-house.ie/
ISOQUICK: https://www.isoquick.co.uk/

ICF BUILDING SOLUTIONS: https://www.icfbuildingsolutions.co.uk/
PASSIVE SLAB: https://passiveslab.ie/
JACKON: https://www.jackon.co.uk/
THERMOHOUSE: https://thermohouse.co.uk/
ECONEKT: https://econekt.co.uk/
ASPECT NUBUILD: https://www.aspectnubuild.com/
AFT: https://www.advancedfoundationtechnologylimited.co.uk/

 

[Iceverge]

With a timber frame you can mitigate the issues with the floor wall junction pretty easily with a normal strip foundation. 

 

Insulated rafts not as advantageous as they would be for a cavity wall or EWI house.

 

What is your preferred TF buildup? What do you propose as external cladding?

[MikeSharp01]

We used AFT - they worked very well with us, they did the structural work with our SE, supplied the Kit, and supported us all the way. We prepared the ground, set out the kit, did the rebar work, attached the UFH to the mesh and poured the concrete ourselves.

[Dunc]

I've been struggling with this recently too. "design, supply and do all the work" is apparantly a big ask.

I've contacted everyone on @garrymartin's list and more. I only found 2 willing to get even close to your requirement:

 

MBC will design, engineer (subcontrated), supply and install from -150mm MOT to concrete finish, but the underbuild is still your job. And presumably will only do this if you're buying their frame too.

Econekt will design, engineer, supply and install, but only starting from the formwork. All underbuild, service install, and the blinding layer are your job. I don't see much value in this proposition as getting the blinding layer flat with services in the right place will be half of the critical part of the install (the other half being getting the formwork square. Happy to be corrected on this).

 

Everyone else I contactetd are desing/supply (+/- engineering) only, no install.

AFT will design, engineer & supply but no longer send someone to site to supervise.

Greenraft are similar to AFT but claim to have a network of installers...except in the highlands.

 

If you can find a groundworker who has experience with insulated rafts (ask the suppliers who they've worked with) then you're probably good to go with any of the desing & supply companies.

[IanR]

6 minutes ago, Dunc said:

AFT will design, engineer & supply but no longer send someone to site to supervise.

 

That may explain why Adam at Wilkinson Passiv Homes will now do the ground works as well as the timber frame build.

 

Previously AFT would have supervised the raft install.

[scottishjohn]

not convinced on need for it in this country with our climate ,which is getting warmer all the time 

different story in  sone european countries with much lower  winter temps and long winters

 frost line in Uk will never get down to where it would be 

Edited May 28 by scottishjohn

[garrymartin]

@scottishjohn It's never really about "warmth", it's more about maintaining a consistent temperature at whatever temperature you want that to be. In the summer months, at least some of the time, that's going to be less than the outside temperature. As the climate gets warmer, maintaining a cooler, consistent internal temperature will be even more important.

[scottishjohn]

4 minutes ago, garrymartin said:

@scottishjohn It's never really about "warmth", it's more about maintaining a consistent temperature at whatever temperature you want that to be. In the summer months, at least some of the time, that's going to be less than the outside temperature. As the climate gets warmer, maintaining a cooler, consistent internal temperature will be even more important.

ok - thats no problem just up the insulation thickness on top of your sub floor concrete slab- cheaper and easier to do -fix UFH to it  ,then screed the pipes in  

 your constant temp will come from no air leaks and good insulation next to living areas

 or  just put a row of ICF blocks at bottom to get you out of the gound?

Edited May 28 by scottishjohn

[JohnMo]

 

3 hours ago, Mark Greenfield said:

We (my wife and I) like the idea of a passive foundation slab,

I did look, no one wanted to come this far north, so just did standard stripped footings and stub walls and did plenty of insulation below and sideways to stop heat loss as much as practical. Easy to get contractor to do that without much learning curve.

[Mark Greenfield]

2 hours ago, Iceverge said:

With a timber frame you can mitigate the issues with the floor wall junction pretty easily with a normal strip foundation. 

 

Insulated rafts not as advantageous as they would be for a cavity wall or EWI house.

 

What is your preferred TF buildup? What do you propose as external cladding?

Cladding will probably be a mix of masonry and timber, but that all depends on final design and planning. I'll go for a u-value of 0.12 or less which is pretty straightforward and most TF companies seem to offer that as an option for peanuts. That said, I may opt for a masonry cladding all over and then clad - depends who I use for a mortgage.

[Nick Laslett]

I used a local Suffolk firm for the groundworks, Kore for the materials, Tanner for the design and MBC team at weekends for assembling the EPS, reinforcing mesh, DPM, UFH, etc. They then did the pour and the power float. 

 

The only company I have in my bookmarks that @garrymartin hasn’t listed is:

 

https://futurefound.co.uk

 

But I never contacted them, so don’t take this as a recommendation. 

[Iceverge]

1 hour ago, Mark Greenfield said:

Cladding will probably be a mix of masonry and timber, but that all depends on final design and planning. I'll go for a u-value of 0.12 or less which is pretty straightforward and most TF companies seem to offer that as an option for peanuts. That said, I may opt for a masonry cladding all over and then clad - depends who I use for a mortgage.

 

You could stick frame it and cut out some of the costs of kit build like cranes etc. 

 

Not to mention the risks of handing £££££ upfront to a TF company. 

 

 

[Gone West]

7 hours ago, Mark Greenfield said:

I'm looking for a company to do it all for us, and we take over from there (with a timber frame)

That's what we did. Isoquick insulated slab and TF.

[scottishjohn]

8 hours ago, Mark Greenfield said:

We had a similar scenario with screw piles, but that's another story - just odd there isn't a bit more 'joined-up thinking' for these things.

you are talking about the building trade --lot of muscles  but not a lot of common sense -they will just follow the plans --so any good thinking has to be at the beginning and thats hwere a GOOD architect comes inwith lots of detail on how things go together 

[Tom]

1 minute ago, scottishjohn said:

they will just follow the plans

if you're lucky

[scottishjohn]

Just now, Tom said:

if you're lucky

thats why you need to understand them yourself and keep checking on them 

I have hada couple of minor run ins with my builders  ,but they know now i willspot what they are up to --so don,t cut corners anymore

Iam very happy with my choice of builder and have very few ,mch feqwer than i expected minor problems with  them  than i expected. and they have respect for what i am doing outside  now --now they can see I am nmaking a good job of my part of the job

 

 

 

[Mark Greenfield]

On 28/05/2024 at 17:03, Gone West said:

That's what we did. Isoquick insulated slab and TF.

Isoquick did the lot for you? Design, supply and installation (including all site prep work)?

[Mark Greenfield]

On 28/05/2024 at 16:42, Iceverge said:

 

You could stick frame it and cut out some of the costs of kit build like cranes etc. 

 

Not to mention the risks of handing £££££ upfront to a TF company. 

 

 

Problem with stick-build is that I know my lender won't accept it. We need to provide "third party accreditation" - ISO9001 or something like that. As far as I can tell, these accreditations can only be applied to factory-made products so stick-building won't be an option. I've used stick-build for extensions before, but for my next home it's just not an option. Factory-made timber frame will also be a lot faster on site, and less dependent on weather etc.

[Kelvin]

21 minutes ago, Mark Greenfield said:

Problem with stick-build is that I know my lender won't accept it. We need to provide "third party accreditation" - ISO9001 or something like that. As far as I can tell, these accreditations can only be applied to factory-made products so stick-building won't be an option. I've used stick-build for extensions before, but for my next home it's just not an option. Factory-made timber frame will also be a lot faster on site, and less dependent on weather etc.

How does your lender manage the financial risk with a timber kit. Generally the kit companies want the money up front paid in stages  which they might have for several months before the kit is supplied. The kit company goes bust in the meantime and the money is most likely lost. This has happened. Is the lender expecting you to insure against this? 

[Gone West]

1 hour ago, Mark Greenfield said:

Isoquick did the lot for you? Design, supply and installation (including all site prep work)?

They did design, supply and installation onto a level site, which I had marked out and laid all services.

 

[Mark Greenfield]

4 hours ago, Kelvin said:

How does your lender manage the financial risk with a timber kit. Generally the kit companies want the money up front paid in stages  which they might have for several months before the kit is supplied. The kit company goes bust in the meantime and the money is most likely lost. This has happened. Is the lender expecting you to insure against this? 

That happens with builders too (and kitchen companies, window companies, etc etc)! There's no need to insure against it, lenders will lend - and do. Some won't, but it's a tiny amount (Coutts, for example). Buildstore provide mortgages tailored for self-build - and they even do advance stage release so you can draw-down the funds needed in advance of the work being carried out. They don't even ask for vesting certificates. It's a no-brainer; I guess the self-build market is one they want to be in.

 

If anything, working with a bona-fide timber frame company would de-risk a build, surely? All engineering and materials accounted for, accredited manufacturers and installers, the ability to check their credit scores and so on is all possible. 

[joe90]

On 28/05/2024 at 09:50, Mark Greenfield said:

We (my wife and I) like the idea of a passive foundation slab, but can't find a company that will help design, supply and do all the work.

I too was in that situation so went with strip foundations but well insulated like this…