Mouldy shed roof, do I need to replace it?

MassiveJim · 18 Jul 2018 at 18:58

The felt on my shed was worn out and I had small leaks all over the shed. Consequently the whole of the roof on the inside is now mouldy.

Research online suggests spraying with bleach, leaving for a while and then scrubbing off with hot soapy water. I have done a test patch and the timber is still very black.
The roof is made from tanalised tongue and groove.

I have some bitumen sheets and fixings ordered which should be here in a few days.

My question is should I replace the tongue and groove with some OSB or leave it?
I don't know if the black marks left behind are harmless or not?

thezappa · 18 Jul 2018 at 21:59

The black marks are harmless. You can treat the area with some fungicide (like this: https://www.permagard.co.uk/universal-wood-preserver-ready-to-use-5-litres) but the black marks will always be there unless you paint over it.
Give it as much are as possible, could install some louvred are vents for future ventilation.

LuckyBenski · 21 Jul 2018 at 01:50

No point treating mould until it's thoroughly dry, and no point drying it until the leaks are sorted. Ergo, fix leaks > ventilate well > treat/replace mouldy bits.

ANDARIAL · 21 Jul 2018 at 11:57

LuckyBenski said:
No point treating mould until it's thoroughly dry, and no point drying it until the leaks are sorted. Ergo, fix leaks > ventilate well > treat/replace mouldy bits.

While i can see where you are coming from.He cant fix leaks then decide to replace mouldy bits
If he does he has to re roof with new felt again
So i would decide first if you are going to use new boards
if not pull off old felt,let dry for a day or so,treat with wood preserver etc then allow to dry a bit then re roof with whatever

Vents are a good idea too

bremen1874 · 21 Jul 2018 at 12:31

In this weather it shouldn't take long to dry completely.

I'd remove the felt completely and temporally cover it with a well secured tarpaulin. Let it dry, get it treated, and then re-felt.

MassiveJim · 21 Jul 2018 at 13:16

roof was dry already to be fair.

I removed all the old felt and weirdly the top of the roof boards was not mouldy at all..
I have now fitted onduline roofing on top of the T&G and my plan is to treat all the mold on the inside over the coming couple of weeks.
WIll take a little while simply because of moving everything around to make sure I don't cover everything with bleach

bremen1874 · 21 Jul 2018 at 13:20

You can buy chemicals designed for the job that don't involve bleach.

Use one of them and you won't need to worry so much about it getting onto other stuff (or yourself).

MassiveJim · 23 Jul 2018 at 01:25

bremen1874 said:
You can buy chemicals designed for the job that don't involve bleach.

Use one of them and you won't need to worry so much about it getting onto other stuff (or yourself).

do you have a link ?