Condensation in loft, trickle down chimney breast

[JohnD]

you can slot the plastic lids with a hacksaw, or a breadknife, or a sturdy pair of scissors.

plenty of ventilation in the loft is good, as it will take away (a lot of) the water vapour

 

[NeilFawcett]

you can slot the plastic lids with a hacksaw, or a breadknife, or a sturdy pair of scissors.

OK, I'll measure up, order, and chop

I'll plug the gap around the chopped out wedge with some plastic bags/insulation to make it better.

plenty of ventilation in the loft is good, as it will take away (a lot of) the water vapour

Well, I've checked the insulation wasn't blocking the sofits, which it was in about half a dozen places.

But to be honest I recon the condensation must be down to:-
1) Time of year/weather conditions?
2) My chimney leak - Moisture coming directly into the roof space, which then evaporates.
3) The cold water tank - A huge lump of water which clearly is producing water vapour as the lid is covered in it (underneath), and when I put a plastic insulation blanket on the lid, it's covered with a lot of condensation too!

 

[JohnD]

you can make a single cut in the lid, leading to the hole for the pipe. No need for a wide slot. The lid and slit will flex to go round the pipe. if you put thick Climaflex or similar round the pipe, you can push or trim it to a close fit against the lid.

 

[NeilFawcett]

you can make a single cut in the lid, leading to the hole for the pipe. No need for a wide slot. The lid and slit will flex to go round the pipe. if you put thick Climaflex or similar round the pipe, you can push or trim it to a close fit against the lid.

I'll measure and cut as carefully as I can... I assume the lids are not dome shaped inside thus meaning all the water simply runs out to the edge and down the side of the tank, and instead drops back in again?




This article suggests some condensation is to be expected, especially after improving insulation, which is something I've done over the past few months to some degree at least - http://www.telegraph.co.uk/property...186754/Property-advice-loft-condensation.html

 

[JohnD]

I disagree with the telegraph man when he says "Each time we crank up the insulation in our attics it has the reverse effect of making the roof void colder and in cold or damp weather that will lead to condensation"

The condensation generally occurs on the underside of the roofing felt. This is uninsulated and exposed to the outside air, and will usually be very cold, and even frosted at night. Heat loss through roofing felt is so high that heating the loft will not make the felt warm enough to prevent condensation. The water does not condense in the open air in the loft as rain.

It would be more true to say that insulating the loft makes the house warm, so any escaping warm air will carry more water vapour.

 

[NeilFawcett]

Roofer here - One of the head stones at the top of the roof (next to the chimney) is broken, and another tile cracked too. Replacing today which is useful as bad weather forecast!

I've ordered proper lids for the cold water tank, and expansion tank. Hopefully they'll fit!