Insulated raft suppliers

[kandgmitchell]

Hi,

Decided that we are going to use an insulated raft on our project. Our structural engineer is comfortable with the process and has done an initial assessment indicating a 250mm slab with 2 layers of mesh. Whilst he is busy working up the full calculations/drawings I'm out looking for quotes for the insulation/formers.

 

I've approached isoquick - has anyone any experience of other suppliers that they would recommend?

 

Cheers.

[IanR]

You could possibly get a more "efficient" insulated raft from one of the companies that specialise.

 

A 250mm raft reinforced with 2 layers of mesh sounds over-engineered. What build method are you going with for walls? and are you planning UFH installed within that 250mm?

 

The following is a list of Insulated Raft Suppliers. I had an excellent experience with AFT Ltd. (Advanced Foundation Technology Ltd.)

 

I found a lot of the EPS manufacturers, selling formers for insulated raft foundations, are tied to a particular Raft Supplier, so will only sell their formers via and Engineered package.

Edited November 17, 2023 by IanR

[kandgmitchell]

Mmmm the design has been issued and is a 300mm slab, two layers A393 plus bars and links to perimeter. I was hoping for something simpler for a timber frame.

[IanR]

2 hours ago, kandgmitchell said:

Mmmm the design has been issued and is a 300mm slab, two layers A393 plus bars and links to perimeter. I was hoping for something simpler for a timber frame.

 

That seems completely over-Engineered. I know nothing of you build, but assuming it's not more than 2 storey, and you have reasonable ground conditions (>70 kPa/m² bearing capacity), then a very simple 100mm RC Raft with a 300mm Ring Beam should be achievable.

Advanced Foundation Technology's standard Eco Raft is as per below and will get you close to PassivHaus performance.

 

Slightly more complicated is their Eco Raft Double L, which is PassivHaus level performance, and can take a heavier super-structure.

 

It would cost you nothing to get a ball-park cost:

 

https://www.advancedfoundationtechnologylimited.co.uk/quick-quote-form/

 

Edited November 23, 2023 by IanR

[Nick Laslett]

We went with a Kore foundation designed by Tanner. This was for an ICF build. Raft was 150mm thick, with 250mm ring beam. 
 

Total depth of footings was 800mm. The breakdown was as follows:

 

300mm - MOT Type 3

50mm - Sand blinding

300mm - EPS

150mm - concrete raft

 

The ground make-up was sandy gravel. 
 

I’m not sure if Kore still ship to the UK, I asked them directly to recommend some UK based installers. Back then Kore were being used by MBC Timber Frame for their foundations. 
 

I was very pleased by the shallowness required for the footings. I feel like any experienced ground workers could put in an insulated raft. The actual execution is quite straightforward. 

[kandgmitchell]

Many thanks - that's what I thought about the ease of installation. Mine's a 1 1/2 storey timber frame with rendered EWI. We live on site and I didn't want the mess of traditional mass fill which is a bit overkill for timber frame. Will give AFT a call thanks.

[BotusBuild]

I used Jackon Raft it had 250mm concrete, 2 layers A393 mesh taking ICF walls (Nudura). We also put the UFH pipes tied to the mesh.

 

All done ourselves apart from the concrete pour. See these blog entries:

 

 

Edited November 24, 2023 by BotusBuild

[kandgmitchell]

Interesting, the final design is issued now. 250mm slab after all, two layers of A393 mesh plus cages along external walls and internal load bearing walls with 6 No. 16mm bars, 3 top 3 bottom. 8mm links at 200mm cntrs plus 10mm tie bars back to the mesh at 200mm cntrs all around. 

 

Think I need to brush up my steel fixing skills......

 

Timber frame with UFH laid in insulation on that slab.

 

Will take up recommendations here and speak to them about this.

[kandgmitchell]

Thanks for the heads up. I've got an AFT quote which is dear for the insulation units but uses less concrete and steel compared to my SE's design and a Greenraft quote which utilisies my SE's design but is a couple of grand cheaper for the units. Bewi who make the Jackon system have yet to come back with a figure so I'll try these guys.