Venting bathroom fan out roof via attic

Gordon Gekko

Hi all,

I have an en suite in the house I just bought. It was put in about 5 years ago. There is an extractor fan in it, but it is only vented up into the attic. As winter approaches, I'm worried about all that moisture causing condensation in the attic (I can't see any signs that it has done much damage over the preceding 5 years). Also, I'd like to insulate the floor of the attic, and I really don't want to have problems with insulating material getting wet etc.

Ideally, I'd like to fit a new longer ventilation pipe to the extractor fan, and vent the pipe out the roof. Would it be possible/advisable to do this? The roof is about 40 years old - would removing one tile and venting out there cause probs with the other tiles? I presume I'd have to install some kind of special tile to shield the vent pipe from rain etc.?

Which type of tradesman would I get to do this - a roofer or a general builder?

Thanks in advance for replies!

jack24

Hi,

As far as I am aware its a requirement in building regs that the ensuite (presuming its not got any external opening) is vented to the exterior. We had an ensuite done a year ago or so and the builder vented it through the attic and out the roof. Having it vented into your attic is certainly not good news and I'd imagine you'd need to get it fixed. I dont think its a huge job to be honest, our house is of a similar age and we didnt have too much disruption. I'd say RooferPete would be in the best position to advise on exactly whats needed. Did you have a survey done as a matter of interest when you bought the property? Was anything else extended/altered?

Jack

rooferPete

Hi Gordon,

I love to see people looking out for the small details that can mean so much over time, possibly the reason you don't see any damage is the roof is almost self venting being 40 years old.

That would most likely change when you upgrade the insulation as the roof would not have permanent ventilation at the eaves and the ridge.

There are two ways of venting the en suite one is to fit a pipe flashing on the roof and install a section of 100mm soil pipe with a cowl then use a flexible duct that is fitted to the fan and the pipe.

The other way is to fit a vented ridge tile that is already made to attach the duct to.

The problems with some of the smaller extractor fans can be they have limited power so you need to take the line of least resistance or the duct being colder than the steam will cause condensation and appear as a leak on your ceiling.

As Jack pointed out it should have been done or at least spotted by the surveyor when you were buying the house.

That said there are a lot of new houses where the duct is lying in the attic, a kind of demarcation dispute should the plumber have fitted the pipe or the roofer have fitted the vent tile ?

.

GreeBo

Im looking at doing the same thing and I have seen a few kits that are designed to vent out via the fascia..dunno how good or bad that would be...
My plan is to install a simple fan vent inside the existing wall vent in the ensuite, should increase the ventilitation for the whole bathroom and be nice and neat...

Farls

Option 3 would be running a 4" pipe at a 90 degree bend and putting the fan out on the gable end...depending on what sort of house it is etc.

Save touching the roof and could be done yourself easily.

rooferPete

Hi Greebo,

Depends on the wind at your facia / soffit if it will work properly, the fans are usually fairly low powered and can actually go in reverse if the wind is strong enough.

.

GreeBo

rooferPete wrote:

Hi Greebo,

Depends on the wind at your facia / soffit if it will work properly, the fans are usually fairly low powered and can actually go in reverse if the wind is strong enough.

.

I have a constant gale blowing directly across the opening, to be honest I could just stick in a bit of wavin pipe and it would extract perfectly with the draw it gives...
But a good point none the less...

Gordon Gekko

Thanks for the replies everyone!

In fairness, the surveyor did mention something about it, but there were so many other issues that were more urgent that I just kind of left it and concentrated on the more immediate issues.

Further to your point jack24, I'm sure the building regs do say that bathrooms must be vented to the exterior, but there were so many other issues with this house that I'm not really surprised!! I think the previous owner was a bit of a 'diy enthusiast' - its taken us quite a bit of time/money already to correct his 'improvements'...

Unfortunately farls its a terraced house so we don't have a gable end to vent out of!

rooferPete, would it help avoid the condensation problem you mentioned if I was to insulate the vent pipe in the attic? Would the attic continue to be self venting if I made sure not to block up the eaves/ridge with the insulating material? Given our current shortage of funds, I'm looking for the most cost-effective cure for this! I have a general tradesman who's coming in to do a bit of other stuff, and I'm sure he'd be able to do this - I've been impressed with the quality of his work so far (says he reaching for a bit of wood to touch!) - he previously re-roofed our extension so he knows a bit about roofing. Which of your suggested methods would be the best in terms of cost v. effectiveness?

Thanks again in advance everyone

BaZmO*

Here's some details you might find handy.

Just to re-iterate what rooferpete has already said. You have to make sure that the fan in the ensuite is powerful enough to deal with the pressure losses which occur over such long runs.

As for venting out to crosswinds, a Backdraught Shutter normally (but not always) solves this problem.

B.

jc1001

On a related note do any of you know where I could find some kind of adaptor to bring a 6" duct down to a 4" - some kind of adaptor or something? Have a non-returnable kitchen extractor fan that I want to fit to an existing opening without kncking out a bigger hole. Dublin area would be great.

BaZmO*

jc1001 wrote:

On a related note do any of you know where I could find some kind of adaptor to bring a 6" duct down to a 4" - some kind of adaptor or something? Have a non-returnable kitchen extractor fan that I want to fit to an existing opening without kncking out a bigger hole. Dublin area would be great.

Where are you based?

B.

jc1001

Based in Dublin.

BaZmO*

jc1001 wrote:

Based in Dublin.

This is like MSN!! Whereabouts in Dublin?

B.

jc1001

Dundrum area. Cheers.

BaZmO*

I was trying to get a place close to you but none of them are that close.

I'll give a list of a few places we deal with. They don't really deal with the public but I'm sure they'd make an exception if you just dropped in. Ring beforehand to see if they've got what you're looking for in stock.

Of course you might be able to get them in the likes of Woodies but the places below will definitely have them.

Woodleigh Limited
65a Moyle Road,
Dublin Industrial Estate,
Glasnevin,
Dublin 11.
(01) 830 3311

Aervent Group
Nangor Road Bus. Park,
Nangor Road,
Dubln 12.
(01) 456 8200

Control Aer
Unit 23 Second Avenue,
Cookstown Industrial Estate,
Tallaght,
Dublin 24.
(01) 463 4300

B.

Gordon Gekko

BaZmO*, thanks a mill for that link. As luck/freaky coincidence would have it, the extractor fan in the bathroom just died yesterday morning. I was talking to the electrician and he said it had likely just burned out, so I might as well replace it with a more powerful one - something like the one you recommended and try and vent it out the soffit as per the diagram in the link you gave me.

Any idea if they sell these ones in Ireland? I tried finding a distributor for Ireland on their website but they don't allow you to check under Ireland - they prob cover Ireland from the UK. Names/details of suppliers here (pref northside Dublin) would be great - perhaps the names you gave to jc1001 might have them?

I had a quick look on the Woodies and Lenehans websites, but their ones don't look as impressive/powerful. I may have a prob venting out the soffit though as 3 metres might not be enough to reach the soffit from where the fan enters the attic.

Is venting out the soffit more desirable in terms of being less hassle/messy than venting straight up and out the roof? Thanks again.

BaZmO*

Gordon Gekko wrote:

Any idea if they sell these ones in Ireland? I tried finding a distributor for Ireland on their website but they don't allow you to check under Ireland - they prob cover Ireland from the UK. Names/details of suppliers here (pref northside Dublin) would be great - perhaps the names you gave to jc1001 might have them?

Aervent are an agent for Vent-Axia or you can ring Vent-Axia direct on (01) 450 4133.

Your best bet is give Woodleigh a bell and tell them what you're doing and they should help you out. But as I said before, they don't normally deal with the public but if you drop in they'll help you out at the trade counter and you'd get much better assistance from them than the goons in the likes of Woodies, etc. Just say a friend in the business recommended them.

B.

jc1001

BaZmO* wrote:

I was trying to get a place close to you but none of them are that close.

I'll give a list of a few places we deal with. They don't really deal with the public but I'm sure they'd make an exception if you just dropped in. Ring beforehand to see if they've got what you're looking for in stock.

Of course you might be able to get them in the likes of Woodies but the places below will definitely have them.

Woodleigh Limited
65a Moyle Road,
Dublin Industrial Estate,
Glasnevin,
Dublin 11.
(01) 830 3311

Aervent Group
Nangor Road Bus. Park,
Nangor Road,
Dubln 12.
(01) 456 8200

Control Aer
Unit 23 Second Avenue,
Cookstown Industrial Estate,
Tallaght,
Dublin 24.
(01) 463 4300

B.

BaZmO* thanks for the info - very helpful - cheers.

BaZmO*

Forgot to mention that Vent-Axia fans are quite expensive. The Rolls Royce of the domestic fan world. Quality stuff though.

B.

RicardoSmith

rooferPete wrote:

....That said there are a lot of new houses where the duct is lying in the attic, a kind of demarcation dispute should the plumber have fitted the pipe or the roofer have fitted the vent tile ...

Gordon Gekko wrote:

...but there were so many other issues that were more urgent that I just kind of left it and concentrated on the more immediate issues....

Thats sound exactly what happened for me too. I connected it up myself. While its better than it was, I Would like to improve the ventilation too.