Extractor fan through roof...

[JohnHunter1]

Hello everyone,

We've recently finished (nearly) a loft conversion in our house, which has a shower room with a large opening velux window.

We hoped the building regs people wouldn't insist on an extractor fan...but they are doing, now there seem to be two options.

1) have a fan put through the roof above the shower....but I've been advised that since the fan isn't really necessary and 1) runs the risk of spoiling the roof and creating leaks that 2) might be better.

2) replace the velux double glazed glass with a single pane with a hole ready for a fan, ask an electrician to install and have it passed by building regs, then take out and replace double glazed pane.

Can you advise which seems best to you?

Thanks,

John H.

 

[Alastairreid]

Mechanical extraction through the roof!

It wont spoil the roof or create leaks if installed properly.

 

[JohnHunter1]

Mechanical extraction through the roof!

It wont spoil the roof or create leaks if installed properly.

Only the first comment showed up! So I was going to ask you to elaborate...but in the above quote it's clearer.

Is this common nowadays, and something any decent roofer can get right?

Thanks,

John H.

 

[Alastairreid]

replace the velux double glazed glass with a single pane with a hole ready for a fan, ask an electrician to install and have it passed by building regs, then take out and replace double glazed pane.
John H.

A lot of effort to bypass building regs! you need mechanical extraction..

 

[Alastairreid]

Simple enough job for a competent roofer John.

 

[JohnHunter1]

replace the velux double glazed glass with a single pane with a hole ready for a fan, ask an electrician to install and have it passed by building regs, then take out and replace double glazed pane.
John H.

A lot of effort to bypass building regs! you need mechanical extraction..

OK, thanks Alistair...last question, is it something that any half decent roofer could get right, with modern equipment?

John H.

 

[datarebal]

Its somthing they would do on a daily basis.. not rocket science.

 

[Nige F]

nothing about building generally is rocket science BUT just make sure the "roofer" knows about dealing with any condensation that will form in the pipe

 

[JohnHunter1]

Thanks, Nige and Datarebal,

nothing about building generally is rocket science BUT just make sure the "roofer" knows about dealing with any condensation that will form in the pipe

How should they deal with it?....the plan was to have the fan over the shower try, so any drops formed by condensation will fall back into it, but is there another way?

John H.

 

[Alastairreid]

insulate the pipe.

http://www.cemex.co.uk/bp/pdf/Russell_Abutment_Ventilation.pdf

 

[JohnHunter1]

insulate the pipe.

http://www.cemex.co.uk/bp/pdf/Russell_Abutment_Ventilation.pdf[/QUOTE]

We'll make sure it's tight fitting with the insulation. At the top we'll wrap extra round, but it's bound to be cold there. Any other tips, if not thanks again.

John H.

 

[TicklyT]

Use a condensation trap.

Condensate can be drained through the side outlet without dropping back into the fan

A single glazed Velux may upset the BCO because you will compromise your thermal insulation properties.

Double glazing companies are quite able to deal with requests for DG sealed units for extractor fans, cat flaps etc. but the appearance of a fan in a Velux would be a little... er... inelegant.

Experienced roofers will have had plenty of practice with flues, soil vent pipes extractor fans etc. all penetrating roofs. It's probably a lot harder to find a roof without something sticking out through it than to find one with.

Any possibility of running the fan exhaust down to a soffit vent, or a vent in a gable wall?

 

[JohnHunter1]

Use a condensation trap.
.....Any possibility of running the fan exhaust down to a soffit vent, or a vent in a gable wall?

From all the advice so far it seems best to go through the roof, it's not really practical any other way apart from the window.

It's a terraced house and the shower room has built in cupboards in the space between the shower room and the side nearest an outside wall, which make it complicated to reach the eaves for example.

There is just one other way...to have the fan low down near the floor, as the loft conversion has a lowered floor (or ceiling on the floor below, which gave extra headroom in the loft), there is a way through the wall low down in the shower-room, across the existing bathroom ceiling, and out through a stone wall in the existing bathroom.... but this might compromise the sound insulation between the rooms, and look a bit odd in the bathroom, also the wiring for the fan, probably from the shower-room light, would be more complicated.

If we go ahead with the roof outlet, has anyone used the SRV 10U ventilation slate from Hambleside Danelaw Ltd? Any tips on using these...or should we go for the low down fan described above?

Thanks,

John H.

 

[HERTS P&D]

What about ducting through the flat roof and coming out of the soffit on the dormer.

Andy

 

[JohnHunter1]

What about ducting through the flat roof and coming out of the soffit on the dormer.

Andy

Andy,

There isn't a flat roof,or dormer!

Anyone used the SRV 10U ?

John H.