Insulated Floorboards DIY

[gjw123]

Hi All

I'm looking to insulate my loft and want to replace the current floorboards with insulated ones.

You can buy them pre-made and I'd need about 14m², or around 20 boards, which would come to a cost of around £460. Looking into the product, it states that it is 8-11mm OSB3 bonded to 100mm PIR.

Having looked 11mm OSB3 and 100mm PIR separately, they would cost around £170 together. Can anyone think of any reason why I couldn't just make this product myself for much cheaper? Also, how would I bond PIR to OSB3?

I've attached some pictures to show what I'm talking about.

Thanks in advance!

 

[freddiemercurystwin]

You don't need to bond them together, the screws through the OSB into the joists will hold it altogether.

 

[gjw123]

You don't need to bond them together, the screws through the OSB into the joists will hold it altogether.

Great - thanks. Do you think they're using a specific type of PIR, perhaps stronger to be suitable for weight bearing, or just standard?

If I did choose to bond (appreciate I don't need to, which makes sense), would it just be glue?

 

[freddiemercurystwin]

The cheapest PIR you can source will be perfectly adequate for your purposes, I don't know what adhesive you would use, in the absence of knowing for sure I would avoid to ensure you don't inadvertently choose something damaging, it's unnecessary anyway, absolutely no need.

 

[robinbanks]

Adhering it will improve stiffness slightly, meaning you could get away with slimmer OSB

expanding foam (get a spray nozzle) will suffice, or you can look at expanding urethane glue