Principles for redoing a bathroom in an old house?

[mdfx]

Hi, so I'm familiar with the ideas behind conserving old buildings, use of breathable materials etc. I'm not in a listed building, but it's an Edwardian flat and I'm trying to renovate sympathetically.

Something Peter Ward's book didn't seem to cover was bathrooms. I'd think modern shower-rooms have a a lot more moisture generated than there would have been originally. What advice would you give somebody taking their bathroom right back to brick/studs/laths?

Are bathrooms an exception in that they should be fully "tanked" to keep the moisture inside the bathroom to be extracted by the fan and window? Obviously this applies at some level or I wouldn't bother tiling the shower, lol. But for example, would you use moisture resistant plasterboard throughout and tile all the walls? Or still go the breathability route to some extent?

Am I overthinking it?

 

[CliffordPope]

Am I overthinking it?

Well, I've been overthinking it too.
The bathroom is cold, with solid uninsulated stone floor and walls. Running a hot bath and luxuriating in it for half an hour produces clouds of steam, like in a turkish bath. If I run the extractor fan it causes a cold draught, so I turn it off while I am in the bath, and leave it running after I have finished. It clears the mist, but the walls are running with condensation.
There's no chance of all that "breathing" through the walls. I could insulate the walls, floor and ceiling, but the room would then be too small to get the bath in. The alternatives seem to be either
1) Create a proper lined wet-room with 100% tiles and a drain in the floor.
2) Invent a sort of very oversize wet suit with flexible pipes and extracting to outside. There'd be no need for a bathroom at all then - I could just lie on a sofa in the sitting room
3) Do nothing, and just accept that the Mould Room needs redecorating every year.

 

[Flyfisher]

I tend to favour showers instead of a bath and I've found that a properly tanked shower cubicle with an overhead extractor fan minimises the amount of moisture in the room. I also have lime-plastered walls painted with claypaint and they don't seem to 'run with condensation', which I assume is because the claypaint absorbs a certain amount of moisture and gradually releases it when humidity in the room reduces after a shower. The fan over-run obviously helps reduce the humidity after a bath/shower but I also tend to leave the cubicle door and the bathroom door open for an hour or so, which seems to help everything dry out and not create a 'microclimate' that favours mould growth. In short, ventilation is your friend.

 

[eon]

We’re in the middle of renovating our Victorian terraced house in very much the same way, breathable materials etc.
Our bathroom had a cement render inside and out!

With all of that cement removed. Our plan is to internally insulate the external walls with wood fibre or calcium cilicate for its anti mould properties. Then lime plaster on top. From reading the forum and books, lime plaster seems to do well in bathrooms. We have one wall which is an internal party wall, we will lime plaster and tile this one and put our shower against this wall. We’re also planning to have a lot of ventilation with an extrator and window vents.

 

[eon]

I tend to favour showers instead of a bath and I've found that a properly tanked shower cubicle with an overhead extractor fan minimises the amount of moisture in the room. I also have lime-plastered walls painted with claypaint and they don't seem to 'run with condensation', which I assume is because the claypaint absorbs a certain amount of moisture and gradually releases it when humidity in the room reduces after a shower. The fan over-run obviously helps reduce the humidity after a bath/shower but I also tend to leave the cubicle door and the bathroom door open for an hour or so, which seems to help everything dry out and not create a 'microclimate' that favours mould growth. In short, ventilation is your friend.

Very good to read this experience. What did you do with the floor? I’ve heard that tile on old joists/floorboards has a tendency to crack and break over time.

 

[Flyfisher]

The floor was already very solid and was tiled, but not by me. I think the builders laid plywood on top of the boards before definitely laying some sort of waterproof membrane, then tiling in the normal way, but it was 9 years ago and I can't recall all the details. I can confirm that there have been no problems so far, so it can be done. I think any problems with tiles cracking would be a result of the underlying floor not being rigid enough.

 

[WetWales]

Oh good I’m glad you’re posted this OP! I’ve been wondering exactly the same thing for months!
We’re renovating our old farmhouse , and I want to get it right… in the old farmhouse we currently rent on the next door hill… our bathrooms is awful and mouldy and condensation and wet walls etc… however no proper fan or vent just an open sash window…

I think my plan in our farmhouse is to put duo dry wood fibre board on the stud walls in place of the laths , then lime skim over them - mainly because we’re doing the whole house in lime so may as well do the bathroom in the same rather than use gypsum. Hoping the duo dry board will offer some acoustic improvement to bathroom noises heard in bedroom and hoping the lime will “absorb” and release a certain amount of moisture

I’m planing to put in TWO extractor fans and it’s not a big room, turbo vents out the roof, im Hoping that will be enough with them on for a time after using to reduce the chance of mould and will leave window open mostly always..


I can’t think what else to do as I don’t think using “modern” materials will be any better probably worse, as the rented farmhouse were in suggests.. it’s skimmed inside with new modern gypmsum, over the old lime, and diesnt breathe at all and moisture runs on the walls so I’m hoping lime will act differently.

I hope tiling onto the lime skim on board will not be a failure… but might decide to just tile directly ONTO the duo dry wood fibre boards (from Mike wye )

The floors another question as we’re putting new oak boards down.. do I bother putting them in bathroom only to cover with chipboard and then tile?
I want to put boards down again in the whole house to do it “justice” but also want a tiled floor as wood floors in bathroom freak me out a bit!

Please let me know what you decide!
Sorry much help but also a thinking the same thoughts

 

[a twig]

This thread might be of interest:

Bathroom installation in period homes

I’m hoping some experienced members can ease some of my anxieties about this subject! We’re adding an en suite to a room which has previously contained no bathroom / plumbing. One wall will be external facing, and is currently stripped back to red brick. The floor is suspended timber (first...

www.periodproperty.co.uk

 

[Zebra]

I treated the bathroom like a modern build (although it's not quite the same issue as the bathroom is in a modern part of the house). So moisture resistant plasterboard and tiling.
I just wanted to add here that I've tried an extractor ducting through the ceiling directly above the shower, I've tried an extractor directly through the wall, and nothing is anywhere near as effective at removing moisture as sacrificing the heat in the room, leaving the door shut and opening the window for half an hour after performing my ablutions.

 

[Lacan07]

Hi, so I'm familiar with the ideas behind conserving old buildings, use of breathable materials etc. I'm not in a listed building, but it's an Edwardian flat and I'm trying to renovate sympathetically.

Something Peter Ward's book didn't seem to cover was bathrooms. I'd think modern shower-rooms have a a lot more moisture generated than there would have been originally. What advice would you give somebody taking their bathroom right back to brick/studs/laths?

Are bathrooms an exception in that they should be fully "tanked" to keep the moisture inside the bathroom to be extracted by the fan and window? Obviously this applies at some level or I wouldn't bother tiling the shower, lol. But for example, would you use moisture resistant plasterboard throughout and tile all the walls? Or still go the breathability route to some extent?

Am I overthinking it?

Yes. A modern extractor fan is the bare minimum for a bathroom renovation, and failing that an open window as Zebra points out. Most of the time a bathroom is on the upper floor and less susceptible to the issues of damp, if you want to tile the room then crack on. Plenty of people gypsum plaster the upper floors of their old houses as a compromise to save a bit of money.

 

[paulc]

Once I'm done with the bedrooms here, the bathroom is next on the list. The walls will be insulated, and I plan on using cement board topped of with a lime plaster. Polished and waxed, it should be waterproof, and I won't need tiles.
At 8'x6', it is a typical 1920s sized bathroom, so space is at a premium. Even so, a loss of a couple of inches isn't going to be noticeable. The hopeful reduction of condensation will make up for the loss of space.

 

[WetWales]

Thanks for that link Twig, an interesting watch!
Making me rethink doing the bathroom stud walls in wood fibre board and maybe using something like the video link - elements board in the bathroom.

I don’t really want to use anything in the house with a load of chemicals in but maybe the bathroom is a compromise!

Thanks!

 

[malcolm]

It's good to see this thread. I'm fed up with my bathroom which is coated with waterproof materials. The steam from a shower is hotter than the walls so a load of water condenses on the walls and mould grows.

It's just the same as the pub across the road that is painted with masonry paint. The air warms up in the morning and water condenses on the waterproof paint and the surface goes green and needs repainting every 5 years. There is a nice breathable house close by will absorb that water and let it out again during the day so no mould and no need to repaint.

For my bathroom when I get around to it in the year 3067 my plan is lime plaster and a breathable paint. Might even go as far as limewash in there. Have a shower and water gets sucked into the walls, then dries during the day. It's good to have ventilation during and shortly after the shower in the form of a fan preferably directly above the shower that stays on for a while after the light has been turned off. That'll get rid of most of the moisture. After that just leave the door open of have a humidity controlled fan to dry the rest out. And no mould.

The bathroom is not a compromise other than the tiles that are sensible to have where you will get splashing.

 

[CliffordPope]

There is a nice breathable house close by will absorb that water and let it out again during the day so no mould and no need to repaint.

That's the bit I don't get. The walls are nearly always colder than day-time air temperature, so why does the moisture evaporate? I thought it condensed in the first place because the walls were cold?

 

[Lacan07]

It's good to see this thread. I'm fed up with my bathroom which is coated with waterproof materials. The steam from a shower is hotter than the walls so a load of water condenses on the walls and mould grows.

It's just the same as the pub across the road that is painted with masonry paint. The air warms up in the morning and water condenses on the waterproof paint and the surface goes green and needs repainting every 5 years. There is a nice breathable house close by will absorb that water and let it out again during the day so no mould and no need to repaint.

For my bathroom when I get around to it in the year 3067 my plan is lime plaster and a breathable paint. Might even go as far as limewash in there. Have a shower and water gets sucked into the walls, then dries during the day. It's good to have ventilation during and shortly after the shower in the form of a fan preferably directly above the shower that stays on for a while after the light has been turned off. That'll get rid of most of the moisture. After that just leave the door open of have a humidity controlled fan to dry the rest out. And no mould.

The bathroom is not a compromise other than the tiles that are sensible to have where you will get splashing.

The external wall in my bathroom is lime, that and fan should do the trick.

 

[noj]

We found that three things cured the mould in our shower room.
1. Extractor fan directly over shower cubicle on 15 minutes overrun
2. A squeegee thing from Lakeland that sticks to the tiles and is used diligently after every shower
3. Daughter got a flat and moved out...

 

[Feltwell]

Getting moisture out is key, extractor over the cubicle with a decent over-run if you can. Don't use plasterboard - MR plasterboard is still cr@p - use Elements board, brilliant stuff. Old thread that may be of interest here:- https://www.periodproperty.co.uk/forum/threads/teeny-tiny-bathroom-saga.17602/

 

[CliffordPope]

I fully accept that ventilation will eliminate condensation, but no one else apart from me seems bothered by the fact that ventilation also makes the bathroom cold. A very powerful extractor fan just above your head in a shower or over the bath causes a cold draught, which for me ruins the pleasure of a long relaxing soak in hot water.
As a compromise I turn off the the fan while I am in the bath, but leave it running afterwards. That is less efficient, because it takes much longer to evaporate condensation from a wall than it does to blow steam out before it has condensed.
Also it leaves the bathroom cold for the next user.

If you had the bath or shower inthe car-port there would never be a trace of condensation

 

[a twig]

It’s deja vu all over again @CliffordPope Haven’t you got around to hearing that lobby properly yet?

https://www.periodproperty.co.uk/fo...nstallation-in-period-homes.17447/post-234090

 

[Lacan07]

I fully accept that ventilation will eliminate condensation, but no one else apart from me seems bothered by the fact that ventilation also makes the bathroom cold. A very powerful extractor fan just above your head in a shower or over the bath causes a cold draught, which for me ruins the pleasure of a long relaxing soak in hot water.
As a compromise I turn off the the fan while I am in the bath, but leave it running afterwards. That is less efficient, because it takes much longer to evaporate condensation from a wall than it does to blow steam out before it has condensed.
Also it leaves the bathroom cold for the next user.

If you had the bath or shower inthe car-port there would never be a trace of condensation

I'm right behind you on this one, the temptation to leave the fan off until you've finished is too great. I told my electrician I wanted a manual override on my fan as he was going to hook it up to the light switch, otherwise I'd taking a soak in the dark.