Condensation on walls after new bathroom fitted

[Lower]

I've recently completed a new bathroom and we're having condensation issues.

The old bathroom was the same layout with the same extraction which is through a light above the shower rain head. The significant difference between the old and new bathroom is one wall is fully tiled with glossy porcelain tiles whereas previously they were travertine. Other difference is that the walls are painted with proper bathroom paint as opposed the the previous matt emulsion.

The condensation is visible as shiny water trails on the walls. So far its not causing a problem, but it will eventually.

Showering with the windows open makes no significant difference. I've increased the size of the extractor fan from one that was moving 130m3/hr to a fan that should produce 245m3/hr through the same 100mm flexy duct. The extraction point is directly above the shower head and that has made quite a bit of difference. I can see from a smoke match that the fan does catch a lot of the steam. The mirrors no longer steam up but the shiny trails on the walls are still there.

Any further suggestions? Turning the heating on fixes it, but that's not really an option for this time of year.

 

[JohnD]

do you have cavity wall insulation, and is the night-time temperature for you quite cool? If the mirrors are not steaming up, it sounds like the wall tiles are relatively cold.

You have quite a powerful extractor. If the flexy runs through the loft, take a look at its route. Flexible hoses tend to accumulate fluff, and condensation in dips. A rigid pipe is preferable, sloping slightly downwards towards the outside so that condensation runs out. Look at the grille or vent in case it is obstructed by fluff or cobwebs.

There should be a 10mm gap under the door to allow dry air from the house to replace what is being sucked out.

 

[vulcancontinental]

Hard to describe but the shower is a cubicle but entered through a 'doorway' with a wall above the shower curtain rail. Used to get mould at the top of the shower and on the ceiling. The extractor is in the cubicle but my wife discovered simply closing the curtain after we've finished showering eradicated the problem.

 

[Lower]

do you have cavity wall insulation, and is the night-time temperature for you quite cool? If the mirrors are not steaming up, it sounds like the wall tiles are relatively cold.

You have quite a powerful extractor. If the flexy runs through the loft, take a look at its route. Flexible hoses tend to accumulate fluff, and condensation in dips. A rigid pipe is preferable, sloping slightly downwards towards the outside so that condensation runs out. Look at the grille or vent in case it is obstructed by fluff or cobwebs.

There should be a 10mm gap under the door to allow dry air from the house to replace what is being sucked out.

The walls are solid. It's a 1920's build. The condensation is a lot more obvious on the painted, plastered walls. Shiny marks are visible where the condensation runs have been even when the wall is dry to the touch.

The flexible pipe is new and is under the insulation so minimal condensation. It's an easy run. Relatively short and with smooth bends. The grill is also new so absolutely clean.

 

[JohnD]

Sadly the solid walls are always going to be cold in winter, so condensation will form there.

It is possible to use an insulated backerboard before tiling, but too late now for you.

 

[ree]

Leaving the shower curtains (or shower door) open is the usual practice - to allow moisture to disperse. Closing can create conditions for mold growth.

An inline motor & rigid ducting is best practice.

Combined light & extractors are notorious for being ineffective installations - done separately was the norm for us.

With advice from the extractor Mfr's, trickle venting, after the initial blast, gives good results.

Sparkies forum might give better advice?

 

[Tipper]

What heating is in the bathroom and has it been on to warm up the bathroom fabric before the shower is used?

I find that if I get up early and shower before my usual time, ie the heating has not been on so long, the condensation is much worse than usual.

 

[^woody^]

I would suggest that you had condensation before the refurb, only the moisture was not apparent. Your choice of tiles and paint is now making it more visible.

There will always be some condensation in bathrooms

 

[cjard]

Echo woody's sentiment; your previous wall coverings were highly moisture absorbent, your new ones are not. Moisture on the old coverings would form on the surface and then get wicked into the wall. Over time it would then dry out again - the building breathed. Your new wall coverings just let it sit on the surface. It will probably evaporate away again over time just like the old bathroom did, but if it really bothers you (or if it forms so heavily that it then runs into areas where it's not wanted like the floor coverings) you could use a squeegee or something like a karcher window vac.. Or just ensure that the room is well ventilated and warm

 

[Lower]

I think the comments about the wall coverings is probably spot on. There is a shower exactly where the old one was with a similar rain head, the bath, sink and toilet are in the same place. The only significant variation is that the tiles are now glossy and the walls and ceiling have been painted with a darker colour proper bathroom paint. It must just be much more visible because the condensation is sitting on the surface rather than being absorbed.

What is making it worse is that there are silvery trails where the condensation has run down the walls in places and even though the condensation has dried up the trails don't completely go. I'm going to give the walls a good wipe down with a damp cloth and see what happens from there. I'm also going to leave the towel radiator on all the time on low to keep the room that little bit warmer.

 

[Lower]

Having wiped down the walls and got rid of the trails, the new extractor fan and heated towel raid on seems to have substantially improved the problem.

For whatever reason, the old condensation trails seemed to attract further condensation drips, making the problem look worse that it was after the new extractor was put in.

However, there is substantially less condensation now. Certainly nothing that concerns me.

Thanks to every one that contributed to this thread.