Bathroom floor preparation

[GNC]

Hi

We have a ground floor WC which we are looking to convert into a WC plus open shower area (kind of a wet room). The space is a bit tight.

The floor is concrete and I was thinking of tiling on top of it, but am worried about how cold the flooring may get in winter. Is there any insulation I can use. I don't want to use underfloor heating as I heard bad reviews about them.

We also have an upstairs bathroom, which has vinyl flooring. We previously had a water leak which left a stain on the ground floor ceiling. We are looking to tile the bathroom floor, but before we do this, we will be putting marine ply on the floor board. Is there anything else we can do to protect against water leaking to the ground floor?

thanks in advance

GNC

 

[tpt]

underfloor heating is the only real way to ensure its warm - the newer systems are pretty good.

Most u/floor heating manufacturers suggest using a backerboard for insulation purposes to make the heating more efficient so this may help but ultimately it will still be cooler.

if you are looking at an open shower area you'll probably be best off using a preformed wetfloor base anyway which you would tile on top of. this would seperate tiles from concrete in that area. see this http://www.kaskadewetroom.co.uk/overview.htm

upstairs depending on the state of the existing floor you could use a backerboard again and then tank the whole floor which would make it more of a wetroom type installation.

 

[Richard C]

Even a ground floor wet room floor must be tanked. For insulation you can overlay with insulated backer board such as Marmox;
http://www.insulationexpress.co.uk/Tile-Backer-Board/Marmox-Waterproof-Insulation-Boards.htm
provides insulation & tanking when properly fitted. Electric UFH is generally not very efficient due to warm up time unless you turn it on 30 minutes before use or leave it permanently on; they can also be expensive to run.

What are the “floorboards” in the bathroom upstairs? I generally prefer to replace the floor with 18-25mm WBP before tiling regardless; thickness you need depends on floor joist size/pitch/span. If they are timber floor boards you can overboard but they must be well fixed, flat & in good condition. Backer boards must be laid in accordance with manufactures instructions. Ply overboard should be minimum 12mm WBP fixed into joists ever 200mm not just into the top of existing floorboards (check for pipes & cables first). You don’t need expensive marine ply, WBP uses similar waterproof adhesive for the plies, just doesn’t have the decorative veneers which you don’t need. Seal the back & edges with SBR primer before lying & support any cut edges with noggins.

Use only quality trade tiling products not cheap DIY, it’s generally crap ; only prime if addy manufacture recommends it; not usual with powder addy; never use PVA.

Read tiling sticky & forum archive posts for more info & to avoind making poentially disastrous & expensive mistakes.

 

[GNC]

Many thanks for your responses.

The first floor has timber flooring.

If I use Marmox Waterproof Insulation Boards on the floor and wall, then do I still need to tank the area?

Also, for tanking do I need to buy specialty product or can I just use the waterproof membrane they sell at B&Q and apply some flexible adhesive?

thanks in advance
GNC

 

[Richard C]

Use Marmox waterproof tape on joints & corners, further tanking is not required. This link contains all the installation information you need;
http://www.marmox.co.uk/

I would not advise you try to use a damp proof membrane as a tanking membrane under tiles.