Extraction Fan - Utility Room

[LookingOptimistic]

I am trying to find out what method of ventilation we need building regs-wise for our utility room.

We are currently in middle of converting our integral garage half of which will be a utility, with sink/washing machine/condenser drying machine etc.

Project guy mentioned putting in a roof vent through ceiling, as there is a single story roof section on our house at front of garage that it can vent through - i have tried to read up on buildings regs and think this possibly comes under a 'passive ventilation strategy' but dont know if its enough for building regs?

Or do we have to have an electric mains powered extractor fan triggered by light switch or moisture detection system still?

I’m looking in to the same at the moment. From what I have read you need an electric fan that extracts 30ls a sec for utility rooms or 110m3 an hr.

@Bells1976 Yes, this is what i read but didn't know if the passive roof could be enough perhaps not.

I will contact the building control guy assigned to the project and get the definitive answer i guess.

Will it have a window? If not then I’d highly recommend an extractor even if building regs don’t require one (although iirc they do). Our windowless utility gets incredibly humid as we dry clothes in there and I think it would be mouldy by now if we didn’t have an extractor.

Also recommend painting the walls in eggshell for the same reason.

@minipie thanks, we usually use a dulux paint for kitchen/bathroom thay are washable - i guess thats ok right?

Yes, i see your point. I have been using it as a utility whilst being a garage and there is no moisture build up because its bare brick and has natural ventilation through gap between garage door and sloped floor xD ha!

When my dryer was in inside room without extractor (was a tiny room) it did cause moisture build up and mould on the walls, so it is highly likely with proper extraction i guess.

Honestly even if the building regs says the passive is enough, I think you will regret not putting in proper ventilation, as damp will tend to accumulate and make the whole thing awful.

I have a utility room which has the equivalent of your passive ventilation and am looking to put in a proper fan, as it's totally crap.

@CatherinedeBourgh Ah enough said then, i will make sure one is installed regardless as definitly don't want this issue - im lucky in that none of my late 70's build house has any current mold/ventilation issues, so i certainly don't want to create any!

Can you not go through the wall rather than the roof?

@tanstaafl the roof was the idea because there is lack of space on the only outside wall of this room, due to fridge/freezer cupboards going in.

We will just have to make room for it though!

I remember looking at extractor fans for our bathroom. The amount of air a 150mm-diameter wall fan extracts is many many times more than a 100mm one. Probably worth the few extra quid (and wall space).

PS Can't an electric fan extract through the ceiling if wall space is a problem?

Extractor can easily be ducted up through the ceiling

Put an extractor in and it will be a fab drying room.

Passive stack ventilation is a whole house system of inlets and outlets, it does work nicely if designed right but you can't do one room afaik.

We had to put an extractor in when we did our utility room. Building regulations state you need one (in Scotland anyway)
It’s on the utility ceiling and the duct runs in a space between the ceiling and the floor above with the exit grate in the outside wall above the door.
It has a separate switch to the light switch so doesn’t automatically go on when the lights on.
It’s needed when we have the dryer on. Room gets lovely and warm without having condensation and wet walls.

I think you're making the right choice to have an electric extract. Consider a continuous running one (possibly with humidity detection) as over 24 hours they move a lot more damp air than the ones that just come on for 15mins with the light switch.

And try to minimise the length of any ducts, as they make extra work for the fan by adding resistance to the moving air. It can reduce the effectiveness. And if the duct passes through an uninsulated section (eg in the roof) it might also get cold and collect condensation.

@LauraNicolaides @minipie ah yes, if it can be a ceiling one that would be good. Its not far to duct out the lower sloped roof, and the roof soace will be insulated up there.

@ValerieDoonican i will see if we can find a quiet continuous one if not too expensive!

I had a humidity controlled one but it was a bit crap and seemed to detect and come on according to the weather outside rather than inside. Maybe installed wrong, who knows. It’s now the usual light controlled arrangement and I just leave the light on when the room is especially damp 😳

Continuous would drive me mad in our case, as it’s under our bedroom and I would hear it. So do consider this OP. But I suppose continuous with a timer wired in to switch it off at night could work.

It’s on the utility ceiling and the duct runs in a space between the ceiling and the floor above with the exit grate in the outside wall above the door.

that’s what I meant to say earlier!

if you’re converting a single story garage you have a small loft space ?
you can put the extractor and ducting in that space then you have to vent out into air. It sounds like you only have sloped roof in that loft though.

some thoughts:
if you’re putting one extractor in , why not two, each with their own extraction point but on the same switch using the same ducting.
You can buy insulated ducting , the idea being the warm moist air won’t condensate in the loft space but will make it outside.
Somewhere in the ducting needs to be a backdraft flap to prevent cold winter air coming into the room.
Get a timer installed, unless you’re happy to leave them running for hours or weeks ( if you forgot and went on holiday )
A decent humidifier will also help.

@tanstaafl Yes through ceiling with ducting through that single story loft soace out roof the building control guy is happy with (its an integral garage just a small slice at front has the single story sloped roof).

Room size is only 3 x 2.2 metres, so think 2 extractors might be overkill. As washing will be hung up drying in there i am inclined to have the silent continuous running one - can get some as low as 10 to 20db, maybe with a boost for when dryer is on and higher moisture level.

I have also seen ones which have the flap to prevent cold air getting in from outside, so will make sure that is considered.

Do you know any good extractor models that you know have been tried and tested?

From the sound of it you’ll need an ‘in-line’ extractor ( meaning it has ducting either side ) , gives you’re going out through a sloped roof.

Ive used Manrose in the en-suite and bathroom mainly for their price vs performance.

As a starter here’s Screwfix’s range of extractors to show the variety and range of prices https://www.screwfix.com/c/heating-plumbing/extractor-fans/cat840510

@tanstaafl thanks very much :) i will take a look!