Detailing - external skin below DPC

[Iceverge]

I'd be tempted to put an aluminium sill dripping into an channel drain to deal with this with insulation behind. 

[gravelld]

For context: the EPS vs XPS below ground battle had been going on for some time. Most specifiers state XPS because in theory it shouldn't absorb water. Others say in practice it does, over time, and EPS dries out better.

 

I'd be very wary of using PIR in this situation. Once it goes, it goes, and you'll have a lot of soggy ineffective insulation.

[Conor]

For our basement, the builder used PIR below ground and we switched to EPS above ground. I've some bits to do that weren't done in PIR and I'm using EPS100 - absorbs less water than EPS70. EPS200 is the best option but I've already spent a grand on the EPS100 before I found this out!!!!

Edited October 26, 2021 by Conor

[Hilldes]

  On 26/10/2021 at 13:07, Iceverge said:

I'd be tempted to put an aluminium sill dripping into an channel drain to deal with this with insulation behind. 

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Yeah, I'm thinking a cill like this.... - in turquoise that oversells the insulation and whatever covering I'll use on the outside of the insulation.

 

I did want to specify cills with the bifolds but the supplier did not have them as an option. I know of a company that produces pressings to order (they produced the cills for my Velfac order). I'll need to continue the external covering for the insulation into the reveal - which might be easier with render than other options such as slate.

 

Not sure though on the need for a drainage channel - given the paving will be some way below the cill and will be sloping down away from the house.

[Hilldes]

  On 26/10/2021 at 15:49, gravelld said:

For context: the EPS vs XPS below ground battle had been going on for some time. Most specifiers state XPS because in theory it shouldn't absorb water. Others say in practice it does, over time, and EPS dries out better.

 

I'd be very wary of using PIR in this situation. Once it goes, it goes, and you'll have a lot of soggy ineffective insulation.

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 Thanks @gravelld would be tempting to use PIR given I have some left over from inside, but somehow does not seem right below ground.

[Hilldes]

  On 26/10/2021 at 15:52, Conor said:

For our basement, the builder used PIR below ground and we switched to EPS above ground. I've some bits to do that weren't done in PIR and I'm using EPS100 - absorbs less water than EPS70. EPS200 is the best option but I've already spent a grand on the EPS100 before I found this out!!!!

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Thanks @Conor, where did you buy the EPS 100? When I search for EPS 100, EPS 200 etc. the results returned don't appear to be to this specification e.g. the product is 100mm thick, but nothing to say it is EPS 100. 

[Conor]

If it's advertised as floor insualtion, it'll be eps100. I got mine directly from Kore.

[Iceverge]

  On 26/10/2021 at 18:34, Hilldes said:

 Thanks @gravelld would be tempting to use PIR given I have some left over from inside, but somehow does not seem right below ground.

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I think any plastic insulation will be just fine so long as it's not sitting in a pool of water. 

 

That sill looks A1 so long as it won't break from someone standing on it. 

[Hilldes]

  On 26/10/2021 at 21:43, Iceverge said:

That sill looks A1 so long as it won't break from someone standing on it. 

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That is the key challenge I think as it will be cantilevering 70mm.

[Hilldes]

@Russell griffiths are you rendering just the visible above ground section of the insulation or the buried section too?

[Russell griffiths]

  On 02/11/2021 at 12:47, Hilldes said:

@Russell griffiths are you rendering just the visible above ground section of the insulation or the buried section too?

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All of it. 

 

If you want that aqua base, then you might have problems, I’ve just been told none available until the new year. 

[Hilldes]

So the area below DPC is now completed. These are JUB products:

 

50mm XPS Insulation - fixed mechanically and chemically (the glue was the same product as base coat render I think). Fixed to 140mm concrete blockwork.

 

 

Base coat render (right) then primer for top coat (left)

 

Top coat render