Damp loft caused by shower usage?

During the winter I have noticed that my loft gets very damp. The felting on the north/rear of the house feels wet to the touch and water drips off it. Areas of chipboard flooring have distinct water marks and a laminated bit of chipboard had a layer of water on it. Now that's not good!

My loft space has fiber glass insulation covering the floor. The soffits are open and ventilated and I have a breather gap in the brick work on the side of the house.

The previous owners had a Drimaster ventilation unit fitted in the loft. Now I guess this draws in air from the outside into the loft space (thus ventilating it) and down into the house. Not much use since, for a lot of the time, in winter the air tends to be damper outside than inside. Our washing is conveniently dried using a condensing tumble drier during the winter months instead of slinging it on the radiators. Nice.

Anyway, I always assumed that the damp loft was caused by damp air outside working its way into the loft space and condensing onto the cold , north facing felt.

Now, I like a good hot steamy shower in the mornings to wake me up. A lot of steam is generated in the bathroom. The bathroom is at the rear/north facing side of the house. When I have finished, I open up the bathroom window as much as I can to let the moisture out. I was watching it this morning, billowing outwards and upwards towards the ventilated soffits. Hmmmmm, could this be the source of all the dampness? Lot's of warm moist air rising up through the soffits into the loft space until it hits the cold felting and condenses out?

I think I should experiment by not having showers for a week (ugh!) or simply keeping the window shut.

Any further ideas or suggestions?

Has anyone used a Drimaster ventilator?

Thanks.

Reply to
Rob Horton
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Are you sure the drimaster has not been connected 'in reverse'? if it were set up to draw air from the house and release it in the loft you woul dget the problems you describe.

I'd start, anyway, by switching off the drimaster. It's less stressful than stopping using the shower for a month.

Robert

Reply to
Robert Laws

I know you'll not like this idea, but I have noticed a massive difference in steam generated between having the shower on the default max. seting (where you press the button on the temp knob to go hotter) as is used for my partner and son, compared to 10 degrees hotter for that toasty hot shower we like to indulge in.

Try showering cooler for a few weeks and see what happens. A bath as hot as your hot shower will surely give just as much steam.

Reply to
PeTe33

"Rob Horton" wrote

Do you have water storage or header tanks up there? They can create condensation in a cold loft

Phil

Reply to
TheScullster

I've only used the Drimaster for a few hours recently just to see what happens. It draws air out of the loft space into the house. I have checked.

The only water storage is the cold tank for the the hot water cylinder that is in the airing cupboard in the bathroom, oh and the small tank (cold water) for the central heating system. I wouldn't have thought that they would have created much condensation since they are covered by lids. Besides, it's a LOT of condensation. You can see it running down the roofing felt.

Reply to
Rob Horton

You mention soffit vents,check that the loft insulation is not blocking the flow of air from these vents,where the roof joists meet the ceiling joists quite often insulators install the insulation right up to roof felt.It is also possible to install additional roof vents through the tiles,these are a universal fitting

Alex

Reply to
Alex

I have met seen this situation two friends houses, dripping condensation from roof felt in spring ans autumn. One had so much it dripped onto a plastic container, leaked through the lid and filled it up about 1/2 an inch deep.

One friend solved it as follows:-

- Fitted trickle vents to his wooded framed double glazing upstairs. Driledl holes, added plastic covers from double glazing shop.

- Fitted a dehumidifier on his landing. Ended up having to plumb in as so much water was being collected.

- As his stairs exited from lounge fitted a curtain round the bottom of the stairs to stop warm air rising up the stairs.

- Put a door back in the opening from kitchen to rest of house (removed by previous owners).

In the end the last two proved the most effective and since doing has sold the dehumidifier and no longer suffered "rain" in the loft.

The other friend tried the following:-

- More loft air bricks.

- Humidity controlled fans in the loft.

- Finally an "Amber dry" (?) dehumidifier in the loft (£300). Uses silica gel wheel to dry so virtually silent unlike a compresser rehumidifier and works at below 5°C. Again plumbed in as so much water was being drawn out.

Finally I gave him the page on ventilation from my new house owners manual (from 2000) and it said "to prevent damp/condensation problems upstairs in winter ensure the window trickle vents are not blocked and at least one upstairs window is left in vented postion". Well he looked at the trickle vents and they were either blocked with cement or blocked with solid lumps of dust/insects. Cleared them out, left an upstairs window in vented position and no condensation in loft in both this Spring and Autumn first time in 8 years in living in the house.

Reply to
Ian_m

I keep my window shut and I get damp above the shower in the loft. I think my steam or moisture must be leaking through somewhere.

Reply to
adder1969

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