Loft condensation / ventilation

[Timmyk86]

An air brick will inly be any use if it is high enough to ventilate the new roof space after conversion. That sort of eaves (fascia on corbel and dentil brick feature) would require over fascia type vents.

That's great advice, thank you. Unfortunately I'd probably would need a roofer to do that for me!

 

[Timmyk86]

Nice brickwork, good windows.

I'm a bit surprised there is no visible gap at the eaves. Must be a different style of construction from what I'm used to. I'm sure you could bore some big ventilation holes, but someone more familiar with your roof will know better.

Some of those timbers look to me as if they have been badly wet. Prod them with a flat screwdriver to check that they are sound (not with a round or pointed prodder as the marks will look like wormholes)

Taking out that loose brick would help, but you need to prevent rain or wildlife getting in. A plastic airbrick may fit.

Got up there again today to fit some more lap vents and prodded the timbers as suggested. Screwdriver went in about 5mm, wood felt relatively soft on the outside.

What finding should make me worry?

 

[JohnD]

Sounds like it has been water damaged. Is the damage widespread? 5mm is not much on substantial timber.

One action is to scrape away the rotten part and see how thick the sound wood remains.

 

[Timmyk86]

Just picking up on this again. I installed a bunch more lap vents - there are now 20 up there - and I wedged open the laps nearest the ridge so now there is a path for air to the slates at the apex of the roof. The condensation has lessened, but not gone completely.

I've been wondering about over-boarding the lath and plaster ceilings in the upstairs rooms with vapour barrier plasterboard to try and seal the living space from the attic. In my mind stopping the warm moist air from escaping up into the loft would stop condensation. Is this a logical idea?

Thanks
Tim

 

[foxhole]

Usually only source of warm moist air in loft is via loft hatch or poorly positioned vent from kitchen/bathroom/ boiler .

 

[plastic_peanut]

Would suggest finding the source as per Foxhole. Can you turn the shower on run a bath and go up in the loft with a torch?