Sylfaen insulated foundations

[jamieled]

We're working on our building control details at the moment.  The Sylfaen insulated foundation system has been pointed out to us as an option, but until now I've never heard of them.

 

Does anyone here have any experience with them?

 

https://view.publitas.com/p222-14383/sylfaen-insulated-foundation-system/page/1

 

If it's of any relevance, this is for a smallish timber framed house.

 

cheers

Jamie

[PeterW]

Looks impressive ! No mention of a BBA or certification though that I can see ..? Would be very interested to see it in practice. 

[MikeSharp01]

Looks very interesting - why don't you ask then for a proposal against a draft spec. Are you going for a full passive level build? 

[jamieled]

I've seen a couple of docs simply certifying that the system's compliant with English and Welsh building regs under an LABC certification scheme. This statement exists for Scotland:

 

If you would like to discuss a specific use of the product in Scotland it will require an additional assessment under the Scottish Building Regulations and accordingly you should contact the LABSS STAS Administrator at www.labss.org

 

I'm not sure if that means it just needs a SE to do a bit of work and sign off or whether it's a lot more  than that.

 

 @MikeSharp01 not a full passive build, just fairly well insulated/airtight to minimise space heating. I'll speak to them and if I get anything useful I'll report back.

[A_L]

The lambda value of the Glapor is given as 0.078 so a lot of a relatively expensive insulant is going to be required. The thermal bridging of the examples given will be relatively high.

[jamieled]

@A_L thanks, I've done a quick calc to compare a couple of insulated foundation systems and it ties in with your comments on the quantity of insulant needed. I'm not really that knowledgeable about thermal bridging analysis. In this case, is is because in the examples the outer skin block work sits directly on the slab? If we just have a timber frame (no block work outer skin) how does this change(if at all?).

[A_L]

19 minutes ago, jamieled said:

I'm not really that knowledgeable about thermal bridging analysis. In this case, is is because in the examples the outer skin block work sits directly on the slab? If we just have a timber frame (no block work outer skin) how does this change(if at all?).

 

@jamieled, Anytime you can draw a heat-loss path, in these cases down and out through the floor slab and back up to the external air, that does not pass through a dedicated insulation material you are likely to have a significant thermal bridge. It can be mitigated  but will always be present to some degree.

[jack]

The way the slab sticks out from the wall in the top version is not a nice detail at all.

I remember looking into Glapor for some reason before we decided to go with an insulated slab, and I recall it being eye-wateringly expensive. I'd be interested to see the cost of implementing this in the way it's shown, along with the supplier's thoughts on mitigating the thermal bridge.