Working with insulation board

[r_c]

I am trying to build a box to go over my poorly insulated loft hatch. This is the box so far - 4 sides and a lid. The parts are loose at this stage. But I have some questions.

1. Can you suggest a glue to use to stick the 5 parts together?
2. After gluing, can I use expanding foam to fill the gaps?
3. Is there something I can use to 'seal' the exposed edges? The foam seem a little dusty.

20221112_170922 (1).jpg

• r_c
• 12 Nov 2022

20221112_171443 (1).jpg

• r_c
• 12 Nov 2022

I needs to be a box as the loft ladder folds up and sticks proud of the boarding in the loft. I have seen examples on the internet where something similar was built. This is my attempt at using insulation board.

 

[thomp1983]

Foil tape it together

 

[RandomGrinch]

I would use low expansion adhesive foam to glue it together and fill the gaps (remove foil where it's to be glued, so there's foam to foam contact).
Then, as above, I would foil tape the seems and edges.

 

[cdbe]

I used cheap no nails for mine, which looks virtually identical to yours and has been in service for some years now.

 

[SFK]

Note that many find the aluminium tape from Screwfix as being poor (thin).

I recommend the foil tape from Toolstation and Wickes

 

[r_c]

@cdbe That looks amazing. I like the way you only have a small area for the folded stairs to fit into. Yours is more like a nice snug fitted lid, whereas mine is like a simple box. I may end up infilling mine so that there is less air like yours.

Do you have any weather seal (e.g. something like one of these https://www.stormguard.co.uk/product-category/foam-epdm/) along the bottom to ensure a seal between the insulation and the surface it sits on?

 

[Wayners]

Polymer grap mastic.
Following day foil tape.

Nothing solvent based and no nails non solvent it brittle.
All the no nails are obsolete now modern polymers come on market imo

Ob1. CT1. Everbuild ones are good and a bit cheaper.

 

[cdbe]

Do you have any weather seal (e.g. something like one of these https://www.stormguard.co.uk/product-category/foam-epdm/) along the bottom to ensure a seal between the insulation and the surface it sits on?

No, the area around the hatch is boarded and the "box" is quite a bit bigger than the opening and sits nice and tight onto the boarding.