Chipboard Floor

[securespark]

So the insulation just sits on the plasterboard, no need for an air gap?

 

[JohnD]

mine does. I have a room over a garage too. There's no steam or humidity coming up.

I have an air gap under the loft floor, because there are heated rooms (and a bathroom) beneath.

 

[securespark]

Great, thanks.

If we ever made the garage a habitable room, would we have to alter the under-floor insulation?

 

[JohnD]

Can't see why.

 

[securespark]

Just found out that Building Control should be involved in this kind of work.

 

[securespark]

Have spoken to BC inspector, who came to sign off our flat roof.

He says he wants 100mm of rigid insulation under the floor.

He didn't mention it, but is there any point in foil-taping over the joists?

 

[JohnD]

not unless the space underneath is warmer or more humid than your room.

 

[securespark]

Thanks.

I thought 150mm of wool would comply, he says not, hence to 100mm of PIR.

I also have to fit it around the roof, between the cavity and the deck. Joy!

He also reckons there is no need to fit tile vents when I block up the gaps between the cold pitched roof and the warm flat roof. I don't know about that.

I'd be tempted to fit them.

And I've got foil-backed plasterboard for the underside of the warm roof. Now doubting this choice....

 

[JohnD]

Just found out that Building Control should be involved in this kind of work.

How tiresome.

With floor insulation, I have an idea it only applies when you are doing some (large) percentage of the whole house.

 

[securespark]

Well, this is in the same room that has had a new warm roof.

Whether that counts or not, I don't know.

But he's doing it under the same application as the roof, so that's something.

 

[securespark]

Well, I'm more than a little bit miffed today.

When the roof was finished, a BC inspector came. He passed the roof in principle and told us he would issue a completion cert for both the roof and the floor when the floor was inspected part way through the build.

He told me 170mm of wool was no good and insisted on rigid.

Another inspector came today to inspect the floor.

He told me he would have passed 170mm of wool, no need for rigid. But he was happy with the floor. Then he demanded to see the roof (from the back garden) and grumbled that he didn't think the run off was good enough.

I told him the first guy had actually got up there with the roofer and OK'd it, but he was adamant that we should contact the roofer and ask what the drainage detail was like.

I asked him to go back to the office and ask guy #1 about the roof.

We literally went round in circles, him saying I should check with the roofer and that he wasnt happy with the roof and me saying it was fine with the other guy, he passed it and could you go back to the office and discuss it with him.

I thought the whole point of BC was that all the notifiable work was done to the same, recognised standards. Surely the inspectors should all sing from the same hymn sheet?