Insulation advice for filling gap in screed

[Swampy]

Hi, 

 

We’re finishing up a renovation/ extension and are at the point where we put down underlay and engineered wood flooring downstairs.
Unfortunately, our builder left a gap in the screed in the hallway, along the edge of the front door (which of course had not been fitted at this point). 
 

The gap needs to be filled and there’s also a slight draught, so I would like to insulate it. 
 

What’s the best way to handle it? 
Builder said to fill with cement, but that won’t provide any insulation. 
Also, I need this to not be releasing moisture, as the floor will be fitted next week. 
 

Would a piece of Compac foam be sufficient if cut to size? 
Or expanding foam??? 

Any other suggestions? 
 

thanks

[Conor]

What size is the gap? We had to go with a concrete door block for our bifold, so I left a 50mm gap between the screed and then lined the block in aerogel and laid the leftover compact foam in the gap. Foamed into place. Then underlay and laminate on top. Still a slight cold spot but no issues with the flooring. Oh and think I painted the door block in airtight paint as well at tape between the door frame and block.

Edited November 9 by Conor

[Onoff]

What about a piece of 50mm Marmox board? Foamed in with say Illbrück FM330.

[Swampy]

Thanks for the suggestions. 
 

The gap is up to 60mm wide, 100mm long and 70mm deep.  
 

I need to be able to buy something from a shop though, as I don’t have time to wait for online. 
left it late!

[Onoff]

22 minutes ago, Swampy said:

Thanks for the suggestions. 
 

The gap is up to 60mm wide, 100mm long and 70mm deep.  
 

I need to be able to buy something from a shop though, as I don’t have time to wait for online. 
left it late!

 

Email Marmox and ask if there's a stockist near you for 50mm board.

 

https://www.marmox.co.uk/

 

Send a photo of what you're trying to do and they might even send you a "sample" 😉

[Iceverge]

3 hours ago, Swampy said:

Thanks for the suggestions. 
 

The gap is up to 60mm wide, 100mm long and 70mm deep.  
 

I need to be able to buy something from a shop though, as I don’t have time to wait for online. 
left it late!

 

That's a tiny hole. 

 

Literally cup full of sand and cement will have it filled. There'll be about 4 table spoons of moisture in there

 

[Pocster]

2 hours ago, Iceverge said:

 

That's a tiny hole. 

 

Literally cup full of sand and cement will have it filled. There'll be about 4 table spoons of moisture in there

 

I’ve filled bigger holes than that with far less 😉