Bathroom ventilation

[Moosehoose]

I am installing a new bathroom. I need to install an extraction fan pipe and if my roof was not so high then could easily get a roofer to put in a vent tile
and connect the pipe. I expect to get the roofer in this Summer when moving around on the high roof is safer and I can get some other work done.

In the meantime thinking of venting through the soffit as the house is circa 140 years old and I do not think the soffit has built in vents anywhere near where I would put the pipe.

But as a short term measure a friend has sugested why not just vent the pipe to a large unused plastic water tank in the loft with the lid shut.

This seems like a reasonable temp measure to me, or will I be creating too much moisture in the attic?

thanks

[richlist]

We always fit ceiling mounted, humidistat extractor fans. We ensure the ducting is as short as possible from the extractor fan to the outlet grill mounted on the soffit.

They work very well and can be wired so that the fan comes on when the light is switched on or comes on automatically when humidity reaches the pre set level.

[Hardgrafter]

Mine vents into the soil stack (toilet waste pipe that vents through the roof). Guess it depends on your bathroom / soil stack layout. Clearly it makes it easy if your soil stack is in PVC and not cast iron.

[redsturgeon]

Mine vents into the soil stack (toilet waste pipe that vents through the roof). Guess it depends on your bathroom / soil stack layout. Clearly it makes it easy if your soil stack is in PVC and not cast iron.

I would not recommend this course of action.

Also you should not vent into your attic space, into a water tank or otherwise.

The soffit is the easiest place to vent but it must be vented to the outside whichever way you decide to do it.

John

[bionichamster]

But as a short term measure a friend has sugested why not just vent the pipe to a large unused plastic water tank in the loft with the lid shut.
This seems like a reasonable temp measure to me, or will I be creating too much moisture in the attic?

It's the kind of thing you might do for a few days while waiting for the system to be finished, but as a 'temporary' solution for three or four cold/cool months it is definetly not sounding like a good idea.

The fan shifts air (which happens to have water vapour in it), it shifts massively more air than it does water. The tank upstairs can't be sealed because the air needs to get out somehow, if the air gets out then so will the moisture that it's carrying. When that warm moist air gets into you attic the water will condense out on the coldest surfaces making them damp.
In cold weather I suspect a fair bit of the moisture in the extracted air will actually condense out in the tank, but a lot will pass into the attic with the air, how much of a problem that causes will depend on the temperature of the attic, the volume of the attic and crucially how well ventilated it is. I suspect in most situations no lasting damage is likely to result after a few months but if you store anything of value up there that isn't sealed then the dampness could affect it (mould, corrosion), in an old house with old timbers then dampness might revive old long forgotten fungal spores or encourage wood eating beetle to settle or spread in the spring (they like timbers in a certain moisture range), who knows.

Any one who has ran a dehumidifier in a bathroom will know there can be several pints of water in that air, so even if the tank condenses out 75% of the moisture (very optimistically) there's plenty left; you wouldn't by choice chuck half a pint of water (probably more) into your attic everytime you have a bath or shower so think carefully before going down this road.

As an alternative
If the bathroom has a window, can't you just open that when you need to and make use of a dehumidifier for a few hours a day when the window is closed? Or could you rig up a fan to blow through a temporary flexible ducting that you just stick out the window when required until the main fan can be completed? If you have no window then I'd suggest a dehumidifier for sure. Venting into the attic as a last resort only, and frankly I'd rather have no fan than one venting into the attic space.

You might be lucky and cause no problems,I know of a couple instances where I've found bathroom extractors running into large attic spaces and no serious damage was done, but that still doesn't mean it's a good idea.

BH

[Moosehoose]

Thank you for these excellent replies.

Wish I had thought of the soil stack before I encased the new stack with Durgo in a piping cavity, why is the durgo not in the attic (you ask) cos somewhat unluckily the cavity coincided with a massive roof joist. If the durgo ver fails, it can be replaced by the breaking and replacing of one tile.


The attic is very large but yes why throw lots of additional moisture into it.

Back to the soffit, which is so high, I will need to fit the exit grill from the inside, so planning on pulling it up from the ground on string and pulling through the hole in soffit.

Once again many thanks

[Itsallaguess]

Thank you for these excellent replies.

Wish I had thought of the soil stack before I encased the new stack with Durgo in a piping cavity, why is the durgo not in the attic (you ask) cos somewhat unluckily the cavity coincided with a massive roof joist. If the durgo ver fails, it can be replaced by the breaking and replacing of one tile.

The attic is very large but yes why throw lots of additional moisture into it.

Back to the soffit, which is so high, I will need to fit the exit grill from the inside, so planning on pulling it up from the ground on string and pulling through the hole in soffit.

Once again many thanks

I don't think you've mentioned what sort of ventilation unit you're planning on putting in, but from years of experience in trying the ceiling-mounted fans and finding them lacking in terms of air-throughput and also noise, which as we know gets much worse with age with those units, I've had one of these in my loft for a few years now and it's been fantastic -

https://www.amazon.co.uk/MF100T-EXTRACT ... B01G8DM5UA

It's an in-line vent fact, controlled with a built in timer off the bathroom lights, and the air-flow is much, much better than any ceiling fan I've ever used, and it's also much quieter than anything I've used in the past, mainly because it's mounted on one of my main roof-beams rather than the ceiling itself.

I can't stress how much better these are than any of the many other fans I've had in my bathrooms over the years, and if you're doing a loft-based solution to the bathroom-vent issue, and have room up there to fit one of these in-line, then I'd at least have a read of the above link user-reviews and have a think.

It's also a much nicer solution in terms of the bathroom ceiling, because you can make a better choice of nice 100mm grills to put up there, to just connect the flexible vent to the back of, rather than a much uglier fan mounted there. I've got one of these in mine, and it looks really nice -

https://www.amazon.co.uk/Internal-Venti ... B00B0WLL1E

Lots of other types are available - https://www.google.co.uk/search?q=amazo ... 20&bih=908

Cheers,

Itsallaguess

[csearle]

I can't stress how much better these are than any of the many other fans...

I second that, and I also agree that inline fans have the advantage when mounted on timbers that don't transmit much noise to the rooms. If a pad of loft-insulation is placed under the fan when it is affixed then the things become even quieter.

Chris

[stewamax]

Mine vents into the soil stack (toilet waste pipe that vents through the roof). Guess it depends on your bathroom / soil stack layout. Clearly it makes it easy if your soil stack is in PVC and not cast iron.

A bad idea unless you also have an inline one-way air admittance (Durgo) valve between the fan and the stack.
When the fan is off you would otherwise have an open vent to the sewer.

[taylor20]

I can't stress how much better these are than any of the many other fans...

I second that, and I also agree that inline fans have the advantage when mounted on timbers that don't transmit much noise to the rooms. If a pad of loft-insulation is placed under the fan when it is affixed then the things become even quieter.

Chris

I third that, I spent a little more and got one of these:

https://www.tlc-direct.co.uk/Products/S ... 7Qod1YgE3A

I can't hear the fan only the rush of air through the ducting. However I doubt there is much improvement over the Manrose one for my situation, I was just paranoid about spending £60 and it being too noisy.

[PrincessB]

In the short term you might be able to use a dehumidifier to extract the water vapour from showers and baths - It won't do anything to combat smells.

Whether you should consider putting an electrical item not designed to go into a bathroom in there is a reasonable question to which everyone will answer by saying 'Don't'

It does work and also warms the room.

My 140 year old house has a new bathroom in the space that used to be the dining room in a classic two up two down building. I managed to find the space to position an inline fan just outside the bathroom and vent through the outside wall by running the pipes through the space between the beams. It's not as quiet as I had hoped but it works.

Regards,

B.

[jfgw]

I can't stress how much better these are than any of the many other fans...

I second that, and I also agree that inline fans have the advantage when mounted on timbers that don't transmit much noise to the rooms. If a pad of loft-insulation is placed under the fan when it is affixed then the things become even quieter.

Chris

The last one I fitted, I screwed to the nearby wall. The only noise you can hear is the rush of air.

Julian F. G. W.

[Hardgrafter]

Venting to soil stack comments. There is indeed a one way valve on the pipe from stack to the Loo Vent.that prevents smells from coming back into the home. This was all put in by the original builder 40- years ago, and works a treat.

[bionichamster]

I can't stress how much better these are than any of the many other fans...

I second that, and I also agree that inline fans have the advantage when mounted on timbers that don't transmit much noise to the rooms. If a pad of loft-insulation is placed under the fan when it is affixed then the things become even quieter.

Chris

I third that, .

Guess what, I'll fourth that.

I have a the same Manrose fitted in the attic and it is almost silent in comparison with a typical bathroom fan. I have a non-light switch operated variant. Instead it is wired to a run back timer switch enabling me to let it run for up to 2hrs (in 15min increments) but not come on if I just nip into the bathroom for 10 seconds with the light on, works for me. Regardless of how you have it activated these are excellent fans quiet and shift loads of air.

BH

[Moosehoose]

In the end, managed to get a slate vent into the roof and fan now working perfectly.

I think for the next bathroom, I will try and put in an in line fan as it does look like a much more effective solution.

Thanks again

[Loir]

If the next bathroom is in a new house I would recommend a whole house ventilation system with a heat exchanger to retain some of the heat.
Not recommended for putting in the house you are living in. Too much disruption.

Loir