loft condensation after installing halogen downlighters

[Tezbedz]

I have been up to the loft and noticed a lot of moisture, I think it is condensation.

I took up some of the chipboard/melamine and the underside was realluy wet.

We had downlighters fitted about 2 years ago, these are not covered up in the loft.

Are these holes causing the damp, and if so what should the lights be covered with?

 

[JohnD]

the loft is cold.

The house is warm and humid (bathroom especially so)

You have holes in your ceiling which allow warm humid air into the loft. This will cause condensation.

You need to seal those holes in the ceiling to prevent steamy air going up through them. One way is to fit "Smoke Hoods" which are sold to prevent fires and smoke rising through downlighter holes. Or you can make up a simple box out of plasterboard and fit it to the ceiling so it covers the downlighters. Plasterboard is fireproof.

You should not flop insulation over the lamps as they will overheat and possibly damage the electrical cables.

Allow a ventilation gap under the loft flooring.

All lofts need to be ventilated anyway to prevent general condensation, but this most usually occurs on the roofing felt, so in your case you appear to have a localised problem.

If you have downlighters in your bathroom, and if your bathroom has no extractor fan, all the steam is going to rise up through those holes.

 

[Tezbedz]

Thanks John, I saw your posts on a similar subject from a while back and was hoping you would reply.

If I make boxes from plaster board, (I have some left from a previous project) Will I need to seal the inside of the box? If so will Emulsion do?

Am I ok making up the box and attaching it with No More Nails or an equivalent, which should seal the holes.

Ventilation in the loft, otherwise is ok, under the eaves and also where a flue passes through the roof. There is about a 20mm gap between insulation and flooring is this ok

A mate suggested Terracotta Flower Pots stuck above the downlighter with the hole sealed. Is this a bodge or is this feasible?

Thanks again

 

[JohnD]

terracotta flower poits will do as they are fireproof. They will not lie flat on the ceiling though, due to the cable. You can notch plasterboard.

If it was me I think I would nail the bits together and seal the joints with a bit of plaster mix.

You can paint the inside if you want, but I doubt it will matter. If it is a good fit it will prevent airflow so steam will not be sucked up inside the box. It will be warm and dry anyway from the lamp.

 

[JohnD]

Does this help?

http://www.diynot.com/forums/viewtopic.php?p=1080717#1080717

Comments please