The flatroof on my garage is knackered, and I’m in dispute with the builder who is supposed to fix it. Anyhow a tarp was put on to stop the worst of the leaks, and the car has been stashed away for 2 months, largely unseen.
This is what greeted me today, proper furry mould and a car that is now a Petri dish.
When we moved into our present house, the garage roof was in a poor state, so we had new boards on top followed by a glassfibre and resin coating. It’s been on over 8 years so far and is so far fully waterproof.
It’s that time of year when the air is often very charged with moisture anyway so nowhere for any extra moisture introduced via leaks etc to go. Any cold surface will attract copious amounts of condensation, making the detection of the leak source potentially difficult to accurately access. I had a similar issue in the underground void beneath my conservatory where water had found its way up beside the floor membrane. Condensation everywhere convinced me that the wall tanking had failed, it was so bad. The tanking product company KA, sent a representative out to me to prove their product by drilling it to produce dry powder. I cannot recommend this company highly enough as their product is cheap and effective and their customer service superb, even when their product was wrongly questioned. Months later I eventually found a product that sealed the source of my leak and the problem went away. At this time of year it will probably take quite a time for the excessive moisture to exit the building, even when the leak source is identified and remedied. I would consider the use of a commercial heater and/or dehumidifiers to limit further damage to your car, tools, etc.
You will have to identify exactly where the water is getting in and remedy it. It is very likely the roof but the salts on the floor are confusing. I will say from personal experience these salts can form when condensation or water from another source has soaked concrete/cement and then been drawn out to the surface with the drying out process.
Difficult enough keeping stuff dry in a detached, unheated building at this time of year. I try to insulate the MX5, motorbike, etc with thick old curtains and blankets. Not a 100% solution to the detrimental effect of condensation in Jan/Feb but far better than nothing.
Did our own with next door neighbour new boarding, Firestone EPDM one piece so no joints all plastic work cost around £300 for both garages even making a over hang canopy on my side for the times I get caught outside in a down pour… This was about 8 years ago still good has new.
Yes Bruce, I have worked with the newer type products too. I think from memory the stuff I used for replacement and a new build was two layers. Fit well and forget, none of the continuing issues that typically occur with a traditional layered felt roof. The trick is getting the flow and outlets correct to facilitate disposal of rainwater; lots of subtly tapered bits of wood:-)
OP, don’t use traditional mineral felt, do yourself and your property a favour by spending the extra on a vastly superior product that can be fitted and forgotten about.
It’s MGF v MX5
My garage roof has steel Z purlins covered with 18mm OSB then industrial corrugated steel on top which has an anti condensation coating on it.
I have two single skin GRP rooflight panel which cause me condensation problems. dripping onto whatever is below.
I run a dehumidifier all year round in the winter it pulls about a litre a day.
I need to instal some porch roof triwall sheet under the grp rooflights to stop the cold bridging.
