DIY Vent bodge spotted!

[philipuk]

Hi

I've just spotted that the vent in our bathroom roof is literally just a grille into the attic! How much of a problem is this (i.e. how quickly does it need fixing?)

I'm also not sure of the best way of ducting it to the outside. Would a flexible pipe and inline fan through the attic to the soffit be best?

I've also spotted (and jumped on with bleech) some mould around the top of the window and the edge of the ceiling on the outside wall. Does the group have any tips to keep this at bay.

Philip

[Owain]

How long will it take for your attic to go mouldy and rot?

Excellent. Slope the duct so condensation can drain to the outside.

Fit the fan to work properly (humidistat controlled if necessary) and supply background heat to the bathroom.

Use a fungicidal wash on the affected areas.

Owain

[Nightjar]

That depends upon the loft and how much moisture you generate in the bathroom. I've known lofts (slate with no underfelt and the torching all fallen off) that are nearly as breezy as being outdoors.

Flexible ducting is never the best solution. You should be able to find rigid ducting at your local DIY shed. The sort that changes from round to rectangular might be best for feeding out of a soffit. I would probably take it straight up through the roof and stick a cowl on top. Don't forget to include an insect screen if there is not already one in the existing grille.

Good ventilation.

Colin Bignell

[TheScullster]

"Nightjar wrote

Seconded! If you want to do the science bit, look at the VentAxia site for details on duct design. That will show you how the effectiveness of extract fans/systems is seriously compromised using concertina style duct. Don't buy cheapo shed fans, unless you want to replace them every couple of years.

Phil

[chris French]

In message , TheScullster writes

True, but the solution using flexible ducting might be 'good enough' if not the best. In our old house I used a flexible ducting for first part of the run (ceiling vent to fan, fan to rigid duct) as it made mounting the fan a bit easier. Then rigid duct along and up through the roof.

[Lobster]

It should be sorted, for sure; however in terms of urgency - how long has it been like this? If it's (eg) 20 years, and there's no sign of any problem (perhaps because you've a very (overly) ventilated roofspace) I doubt you're suddenly going to develop rotten joists next week.

David