Can I insulate the ceiling of a Wet Cellar?

[JoeCoulter]

Hi All,

I'm a new user, but I think this is the right place for my question:-

I live in an old Victorian Building which has a large wet cellar underneath the the living room. The cellar has a gully around the edge of the cellar floor which feeds into a drain in one of the corners. However its fair to say the cellar floor is still fairly damp (Particularly if there is a lot of rain).

There are at least 2 ventilation bricks abd these are below the ceiling of the cellar.

The living room floor, is pitch pine floorboards on woodjoists, which in turn appear to be above concrete joists.

My problem is the cold from the cellar seeps through the living room floor and makes the room cold (particular on the feet).

What I want to know, is whether I can use insulating boards on the cellar ceiling (Celotex/Kingspan or something else). Basically attach the boards to the concrete joists. Should I put the boards between the joists, or can I attach them to the bottom. If I attach to the bottom of the joists can I fill the gaps above with rock wool, or does this need to be left for ventilation?

Thanks in advance
Joe

 

[TheVictorian]

Sounds like the concrete has been put it at some point under the joists to give them a bit of support, my house has a couple of steels doing the same thing.

If you can get 50mm or even 100mm of Celotex/Kingspan in between the wooden joists and flush up to the floorboards then this will make all the difference. Anything else would be a waste in my mind. Seal any gaps with self expanding foam.

 

[KenGMac]

Joe, Hi.

Do NOT leave any "ventilation spaces" between the insulation and the underside of the flooring.

Obvious but, the thicker the Insulation you can afford / choose the better.

As an aside, if you can access the underside of more floors in your home then why not [as and when finance and time allow] insulate them as well? it can only do 2 things, assist in lowering heating costs and enhance re-sale value?

Ken

 

[JoeCoulter]

Sorry probably a daft addition to my earlier question, however when using the insulating board, do I use the foil towards the cellar, or towards the living room? I assume towards the living room, to bounce the heat back in, but given heat rises I was assuming it might be best towards the cold cellar to prevent the cold going up?

 

[foxhole]

You may find you have condensation dripping from new ceiling if the cellar if very wet, mechanical ventilation may be needed.