1930s Semi ; Novice questions on mouldy roof timber

[MHAD]

Hi. I have some very novice queries about the roof timbers in our 1930s semi. We have just boarded out the loft and fitted proper lighting, so can now see everything clearly for the first time after buying the house last year.

Now that I can see properly in the loft space, I've noticed numerous areas of timber with surface mould. Some of this mould is fine and dark green / black, and some is fine white. Both types come away easily when wiped in most places, but I have found a few stubborn areas. The timbers they are on seem dry in the main, although might feel a little cold to the touch in comparison to others so may have been damp in the past. I've also found some isolated stark white fluffy bits, that remind me of a chrysalis, and are about 1/4'' in length. I don't know what any of these types of mould are, how serious they might be or whether I need to treat them somehow.

I've taken photos of all of this and uploaded them to photobucket in case anyone is willing to take a look and offer any helpful advice ! I'd be very grateful for an opinion before I start spending money on timber surveys and expensive remedies that I don't know will work or if they are even necessary.

http://s89.photobucket.com/albums/k233/richhallx/Roof Timbers/

We cleared out the roof space before boarding it out - all the old clothes, insulation, pictures etc were very dusty but were bone dry. Ventilation seems OK - the cobwebs move about in the draft and you can feel a draft when you're standing still. We've insulated where we haven't boarded, and have kept a gap around the edge all the way round.

I posted a topic the other day about lining the underside of the roof to keep everything clean, using Roofers Choice breathable membrane. Before I do any of this I obviously want to make sure the roof is OK.

Hope someone can help - thanks very much.

 

[JohnD]

//www.diynot.com/wiki/building:condensation_in_houses

 

[MHAD]

//www.diynot.com/wiki/building:condensation_in_houses

Thanks JohnD. We do exercise good general ventilation practice in the house already, however from what I've seen I imagine that the previous owners may not have done. The relevant section in the article looks like...

If you get condensation in the loft, it is probably due to warm air leaking up from the house (especially the bathroom) but it can be due to a plumbing/CH fault putting hot water into the loft tanks. Lofts should be well-ventilated to avoid the risk of rot in the timber. Sometimes loft insulation blocks the air gaps at the eaves, so it should be pulled back a few inches.

Since we have renewed the insulation in the loft we seem to be getting less heat loss into the loft.

Does anyone have any advice on the mould on the timbers?

Thanks

 

[JohnD]

as you have an unfelted tile roof, it will have quite good ventilation (and indeed be dirty and draughty). So if you can prevent moisture getting up there through gaps round pipes or the hatch, and verify that your water tanks are insulated and covered, you only need to spend time up there during heavy rain to look for leaks.

As long as there is no unusual source of excess moisture, it will keep dry.

p.s. those white things are insect or spider eggs in cobweb or similar.

 

[MHAD]

as you have an unfelted tile roof, it will have quite good ventilation (and indeed be dirty and draughty). So if you can prevent moisture getting up there through gaps round pipes or the hatch, and verify that your water tanks are insulated and covered, you only need to spend time up there during heavy rain to look for leaks.

As long as there is no unusual source of excess moisture, it will keep dry.

p.s. those white things are insect or spider eggs in cobweb or similar.

Insect eggs... I hadn't thought of that !

I don't have any water tanks in the loft - rightly or wrongly, we're fed directly from the mains, and have a combi boiler.

I've fitted a new hatch and stop bead - I suppose I could add some draughtproof seal to the stop bead.

We do have some pipes coming in from the bathroom - these only loop back from when the water tank was present, so when I redo the bathroom I can take these below the boards.

Looks like I'm safe to put up the lining?

 

[masona]

Have you thought about using pegboards? For some reason the dusts doesn't goes through the holes in my loft!

 

[Nige F]

Have you thought about using pegboards? For some reason the dusts doesn't goes through the holes in my loft!

Pegboard.........masona AKA Barry Bucknall

 

[memor maplin]

Go into your loft with a nail or a key and press the rafters that have got the staining. If the nail goes in easily you've got problems. If not if the battens and rafters are well ventilated give them a wipe down and leave alone.

Memor