Thicknesses of insulation available to fine-tune FFL

[epsilonGreedy]

I am trying to finalize the proportions of insulation/screed on the assumption that FFL is a full block above the level of the infill blocks of a block & beam suspended ground floor.

 

My architectural technician has unfortunately depicted a 200mm high first course of blocks above the B&B floor.

 

Is there a combination of insulation sheet that results in 160mm of depth that could then be finished with a relatively thick 65mm of flow screed with UFH pipes embedded to bring me up a full 225m high block? 

[PeterW]

Yep - 50mm of EPS, then a DPM and 110mm of PIR and you will be fine. EPS is relatively cheap and will also stop any DPM getting punctured. PIR takes UFH staples much better than anything else. 

[nod]

I used 150 kingspan then 75 mil screed 

With a membrane under the kingspan and a slip membrane on top 

[epsilonGreedy]

32 minutes ago, nod said:

I used 150 kingspan then 75 mil screed 

With a membrane under the kingspan and a slip membrane on top 

 

Non technical factors are encouraging me towards flow screed and from my reading on the subject 50 to 60mm is the norm for flow screed, hence I am looking for an unusual insulation depth of 160mm.

 

75mm of traditional screed feels like a better choice which I assume has a greater heat capacity hence it could soak up more KwH of cheap rate overnight electricity. Also putting aside flex strength concerns with flow screed at 50mm, I assume it would be more prone to hotspots that relate to the embedded UFH pipe network.

 

39 minutes ago, nod said:

and a slip membrane on top 

 

Thanks for the tip, something else to research.

[Russell griffiths]

Are you allowing for your floor finish, wood, tiles vinyl???

[epsilonGreedy]

Just now, Russell griffiths said:

Are you allowing for your floor finish, wood, tiles vinyl???

 

 

No but now I am thinking... should I be considering mobility door threshold levels already? 

 

Flooring will either be some high-end ceramic tile that mimics a French limestone floor or something more sophisticated. I recall offending a retailer at a selfbuild show, "no sir we don't sell ceramic tiles, these are reconstituted stone floor tiles". 

[Russell griffiths]

I was thinking you don’t want to use the word ceramic, nasty horrible stuff. 

[Russell griffiths]

20mm is a fair ol cock up to sort out, you do need to be thinking about your ffl, you cannot call insulation and screed finished, 20 mm of tiles on top will throw you right out. 

Your architect has probably done you a favour. 

No need to be too picky you will just adjust your screed and insulation up or down a bit depending on what height you need to achieve. 

[nod]

42 minutes ago, epsilonGreedy said:

 

Non technical factors are encouraging me towards flow screed and from my reading on the subject 50 to 60mm is the norm for flow screed, hence I am looking for an unusual insulation depth of 160mm.

 

75mm of traditional screed feels like a better choice which I assume has a greater heat capacity hence it could soak up more KwH of cheap rate overnight electricity. Also putting aside flex strength concerns with flow screed at 50mm, I assume it would be more prone to hotspots that relate to the embedded UFH pipe network.

 

 

Thanks for the tip, something else to research.

I finished up putting the screed down myself with my son barowing All 150 metres 

At 56 I should have had more help 

My memories of what I used to get done in a day 30 years ago are a bit distorted

I had intended using a concrete flow screed We tile quite a few now

But just as I was ready for screed I had two ted floors fail on concrete 

It cost me a lot of money even though it wasn’t our fault 

One was the concrete had got under the insulation the other was the clips were showing when we were tiling

The 60 mil that you mention would sort the later But it does leave you with an odd size   

[Temp]

You can get 80mm PIR. Might even get a discount as you will be buying twice as much of one type.