Insulating vs. new floorboards

[samaudio]

Many thanks for all your helpful answers. I am going ahead with lifting the floor and fitting celotex.

Just wondered, what do I do around radiator pipes, when they go up into the floorboards? Do I just cut and fit the celotex around the pipes?

Also, do I just but the celotex up against the brick walls at the edges of the room, then fill any gaps with expanding foam?

 

[geraldthehamster]

Many thanks for all your helpful answers. I am going ahead with lifting the floor and fitting celotex.

Just wondered, what do I do around radiator pipes, when they go up into the floorboards? Do I just cut and fit the celotex around the pipes?

Also, do I just but the celotex up against the brick walls at the edges of the room, then fill any gaps with expanding foam?

Yes, you could fit it round the radiator pipes.

I did seal the edges of the Celotex to the walls at the edges, but I also fixed an upstand between the Celotex and the floorboards, covering the wall.

It's important that any air bricks are not blocked, and still ventilate the space underneath the Celotex. If they are higher than the Celotex, you can make channels for them out of cut Celotex fixed together with foam.

Cheers
Richard

 

[samaudio]

Thanks Richard,
Could you just explain the upstanding you mentioned?

 

[geraldthehamster]

Thanks Richard,
Could you just explain the upstanding you mentioned?

Above the horizontal Celotex abutting the wall, I also stuck an upright strip to the wall. I depends how tight against the floorboards you have the Celotex; you might not need it.

 

[samaudio]

Hello, I'm in the process of this job and currently foil taping the Celotex joins and over the joists.

Just wondered - I know the Celotex needs to be butted up tight against the floorboards, but in some places it's sitting 2mm-4mm below the top of the joist. Is this a major problem? I don't want condensation building up.

Many thanks.

 

[catlad]

That won't be a problem

 

[geraldthehamster]

Hello, I'm in the process of this job and currently foil taping the Celotex joins and over the joists.

Just wondered - I know the Celotex needs to be butted up tight against the floorboards, but in some places it's sitting 2mm-4mm below the top of the joist. Is this a major problem? I don't want condensation building up.

Many thanks.

The Celotex doesn't need to be butted up tight against the floorboards.

Cheers
Richard

 

[samaudio]

Thanks guys.

 

[samaudio]

Hello, many thanks for all help on this. Just wanted to update:

I carried out the work with celotex between joists, all foil taped. Floor went back ok and the result has been a much warmer room!

However, I've noticed that our bay window has large amounts of condensation collecting on the panes. Also, there is a lot of moisture collecting on the wall of the bay, dripping down onto the skirting.

Is this a common problem? Is there anything that can be done? I don't want mould growing.

 

[chappers]

I suspect your bay is poorly insulated and warm air from your newly insulated room is condensing on the cold wall of the bay. You could insulate the inside of the wall and replace the window sills.

 

[samaudio]

Thanks, that doesn't sound like much fun though!
Do you mean dry lining it, and then replacing the sills so that they still stand proud?
Wouldn't the window frames be lost within the new thicker walls too?

 

[chappers]

Insulate with insulated plasterboard up to the bottom of the existing sills which you would then replace to recreate your over hang.
Do you know what the bottom of your bay is constructed of is it timber frame or brickwork.

 

[samaudio]

The whole bay is brick (Victorian terrace 1890s).

 

[samaudio]

But what about the window frame mouldings? Wouldn't they need to be replaced somehow?