Advice on fitting an extractor fan in limited space

[gwebstech]

Hi all

Its just occured to me that ive got to fit an extractor fan in the utility room in a brand new house - to cut a long story short, the house has traditional timber beams so i cant just chop them about, im limited as to what size holes i can cut in them, which means i cant possibly pass a 4" flexible pipe through them and they run in such a way that i have to get through them to get a pipe outside.

Any ideas as to what i can do as its a building reg requirement?

thanks

 

[^woody^]

Use the wall

 

[gwebstech]

i cant get to the wall for the joists running parallel to the wall

 

[stem]

Wall mount the fan so that the duct goes straight through the wall behind it to outside. No need to touch the ceiling joists then.

They can be window mounted, but the double glazed panel has to be especially made.

Ceiling joists are usually on 400mm to 600mm centres. I've never seen one where there is less than 4" (100mm) between them.

Flat ducting is available approx 200mm x 60mm. But the pressure loss will be greater that circular, so a centrifugal fan which produces a higher pressure would be a better bet than an axial fan.

 

[gwebstech]

Wall mount the fan so that the duct goes straight through the wall behind it to outside. No need to touch the ceiling joists then.

They can be window mounted, but the double glazed panel has to be especially made.

Ceiling joists are usually on 400mm to 600mm centres. I've never seen one where there is less than 4" (100mm) between them.

Flat ducting is available approx 200mm x 60mm. But the pressure loss will be greater that circular, so a centrifugal fan which produces a higher pressure would be a better bet than an axial fan.

Ive not made myself clear mate, i can get between the joists, but i cant get through them (ie a hole) to get to the outside wall to expel the air.

thanks

 

[JohnD]

does this room have an external wall?

 

[gwebstech]

does this room have an external wall?

yes mate, but theres joists running parallel that are in my way

 

[JohnD]

if the room has an external wall, put the fan on it, venting through a hole in that wall. Is there a reason why you want to put it somewhere else?

 

[gwebstech]

i see ive been confusing everyone, sorry about that!

the only bit of external wall is only approx 600mm, its where the boiler is going, and in a cupboard, so if i put the extractor there ill have to move the boiler which is why i was thinking to take the vent into the ceiling and then through the wall which obviously wont work

I can only see that ill need to run the flexi pipe to the nearest other external wall and expel it there, its a few metres away so ill have to ask the BCO if thats ok

thanks for the help

 

[^woody^]

Post a picture or plan or something. And send me some anadin.

 

[JohnD]

rigid duct is better.

 

[JohnD]

the nearest other external wall

which room is that in?

 

[gwebstech]

which room is that in?

kitchen

 

[Leofric]

You can't run a ventilation duct through joists unless they are the 'easy-joist' type, so the duct would have to run between the traditional solid timber joists to the nearest external wall which will be acceptable providing you use a suitable fan and the distance is not too great . As others say a rigid pipe or slimline duct could be used.