No Window Bathroom Ventilation

[zad3717]

Hi, We are about to have our extension built and will end up with 3 bathrooms without windows as they are in the centre part of the house... so looking at the best way to get them ventilated.

Ground floor
Shower room 2.7m x 1.2m no external walls or window.

Directly above will be an En-suit shower room 2.8m x 1.8m, there is an external wall here (no window allowed) but neighbour probably won't let me get access to fit grill. (long story)

Opposite across the landing will be a family bathroom 2.6m x 2m no external wall.

I can run ducting in a ceiling void to an air brick, but unsure what would be the best type of fan. Will we be better off with door vents so it allows air to come in to push moist air out?

Any help, pointers etc would be appreciated.
Thanks

 

[tell80]

All this should be detailed in your drawing and text?
Has the proposal passed planning?

Ref extractors: Theres a massive selection available - the sparkie's forum could help you better.
Roughly speaking, go for powerful ext's.
150mm Diameter's worth or equivalent of hard ducting.
And very quiet appliances.

There are extraction terminals available that can fitted from inside the property - high rise flats etc use them.
You hole saw inside the wall, and install the ext's from inside.

Kitchen & Bath fitters do ext's all the time, so do sparkie's - my building firm sometimes use's powerful kitchen ext's in bathrooms

 

[robinbanks]

Will we be better off with door vents so it allows air to come in to push moist air out?

Don't push moist air out of a bathroom and into the rest of the house. Fit an extract fan that ducts exhaust air away to the world

In an ideal scenario you'd look at fitting (including retrofitting to the existing house) a full house ventilation system, with a matrix for recovering heat from the outgoing air. They run in the background at a constant, low level and truly are amazing things for a whole host of reasons (but they cost thousands whereas a basic extractor setup is tens to hundreds)

Has the proposal passed planning?

How do you even know it's needed? This could be a PD extension, and plans consumed by the planning department wouldn't show an extractor anyway

 

[Wayners]

Our bathroom is in centre of bungalow with no window.
Loft conversion above.
Never get any problems as the walls and ceilings are warm from being internal. All condensation is gone in 10 mins.
We have a good but nothing special centrifugal extraction fan connected to long 4m long soil pipe through ceiling void, and a 15mm gap under bathroom door to let air in.
I just have standard paint on ceiling. All looks good at 10+ years old.
I do use window vac sometimes on mirror and tiles after showerm
Oh, ceiling void is packed full of insulation for fire protection. Think that helps

 

[zad3717]

All this should be detailed in your drawing and text?
Has the proposal passed planning?

Yes full planning consent, building regs state just an extractor but I don't think a normal extractor in duct would be enough.

Ref extractors: Theres a massive selection available - the sparkie's forum could help you better.
Roughly speaking, go for powerful ext's.
150mm Diameter's worth or equivalent of hard ducting.
And very quiet appliances.

There are extraction terminals available that can fitted from inside the property - high rise flats etc use them.
You hole saw inside the wall, and install the ext's from inside.

I've seen these so will discuss with builder, neighbour has been an nightmare so don't really want to be speaking with them asking for access over their extension that buts against ours.

Kitchen & Bath fitters do ext's all the time, so do sparkie's - my building firm sometimes use's powerful kitchen ext's in bathrooms

Don't push moist air out of a bathroom and into the rest of the house. Fit an extract fan that ducts exhaust air away to the world

Sorry I was meaning adding vent grill to door to allow cross flow pushing towards extractor.

In an ideal scenario you'd look at fitting (including retrofitting to the existing house) a full house ventilation system, with a matrix for recovering heat from the outgoing air. They run in the background at a constant, low level and truly are amazing things for a whole host of reasons (but they cost thousands whereas a basic extractor setup is tens to hundreds)

Yes costs a lot, and no real way of running all the ducting... I have seen the dMevs though and they may fit the bill.

How do you even know it's needed? This could be a PD extension, and plans consumed by the planning department wouldn't show an extractor anyway

Our bathroom is in centre of bungalow with no window.
Loft conversion above.
Never get any problems as the walls and ceilings are warm from being internal. All condensation is gone in 10 mins.
We have a good but nothing special centrifugal extraction fan connected to long 4m long soil pipe through ceiling void, and a 15mm gap under bathroom door to let air in.
I just have standard paint on ceiling. All looks good at 10+ years old.
I do use window vac sometimes on mirror and tiles after showerm
Oh, ceiling void is packed full of insulation for fire protection. Think that helps

I think keeping the ducts warm in winter is a definite thing I will be doing to stop condensation.

 

[jeds]

Minimum requirement for a bathroom, for basic intermittent extract ventilation, is 15litres/second ventilation to outside air. Choose a fan and ducting that will satisfy that requirement, bearing in mind that length of ducting is a factor so you will need to decide the route of the ducting first and work backwards. Choose a fan with a timed overrun or a humidistat and a quiet one if that is a factor.

 

[zad3717]

Minimum requirement for a bathroom, for basic intermittent extract ventilation, is 15litres/second ventilation to outside air. Choose a fan and ducting that will satisfy that requirement, bearing in mind that length of ducting is a factor so you will need to decide the route of the ducting first and work backwards. Choose a fan with a timed overrun or a humidistat and a quiet one if that is a factor.

Assume a dmev is slightly different because of constant running?

 

[jeds]

Yes, a continuous extract would be 8l/s but dmev is more complicated than that and other factors that must be counted as well.

 

[tell80]

Post #3,
All the drawings I've used for the last, say, 20yrs have had reference, sometimes detailed reference, to extractors.
Often there are separate drawings of elec, heating & AC.
Where three interior rooms become bathrooms then BCO or BCO's office would take an interest.