Washing Machine on Tiled Floor

[colin H]

Hi Folks ,
I am just about to start tiling my kithen floor . I`ll be overboarding onto the existing floorboards .
Were keeping the washing machine in there , and am wondering if the vibration caused may loosen the tiling in any way .
I`m considering cutting out a section of the floorboards and making a concrete base for the washer to sit on . Does this sound practical , or am I wasting my time . I dont want to use thicker overboard than 12mm , as I dont want to create a big step going into the next room .
Any thoughts , please ??

 

[Richard C]

The British Standard & majority of tile adhesive manufacturers recommend 15mm min for WBP ply overboard. Whilst it’s generally accepted that 12mm is OK for light load/traffic area such as bath/shower rooms, a kitchen is a high load/traffic area so you take your chance with that one . Are they actually timber floor boards you have or something else? What is you joist size/pitch/span?

If you want to keep the threshold height down, personally I would replace the existing floor (always my preferred option) with 25mm WBP ply. A little more work but the cost won’t be that much more than over boarding & at least you know where you stand; as long as it’s correctly laid.

The washing m/c should not be a problem as long as the floor is ridged but there are simple steps you can take to isolate that section of floor without tipping loads of concrete in there.

 

[colin H]

Hi Richard - yes , theyre timber floor boards . the joists are about 18 inches apart . Everything seems pretty solid .
Seems a shame to rip them out , but it may be an option . I`ll have a think about it .
You mentioned an alternative to the concrete base . What would that be , please ?
Thanks , Colin .

 

[Richard C]

the joists are about 18 inches apart .

But what is the joist size & span?

Everything seems pretty solid .

To many it always does.

Seems a shame to rip them out , but it may be an option . I’ll have a think about it .

You should! At least they are proper floor boards but they are redundant floor boards, why a shame to rip them out! Over boarding can still cause problems if not done correctly, especially in a kithcen & it’ll be even more of a shame if your tiles crack & you have to rip it all up & start again. A real pain if you’re DIY but not an economic option if you do it professionally!

You mentioned an alternative to the concrete base . What would that be , please ?

Isolate the section of floor the w/mc sits on.

 

[colin H]

Sorry Richard - misunderstood you there ! - you`ll have to speak slowly , Im a DIY-er The joists are 5" x 2" and they span 3M across the room .
Could you tell me the details of how you would go about isolating the w m/c area - do you build a wooden frame underneath it ?

 

[Richard C]

Considering it’s a high load/traffic area such as a kitchen, that’s a pretty small joist for a 3m span, even at the normal 400mm centres, how old is the property? I would be very concerned about flex even using 25mm WBP as a tile base. You may need to beef up the floor by sistering the joists to reduce flexing, if it exceeds the limits of your flexible tile adhesive the floor will fail. You may get away with an elastomeric flexible/single part flexible adhesive but they are a lot more expensive & I wouldn’t like to say without assessing it.

 

[colin H]

Thanks for your reply`s , Richard - I`ll bear it in mind .

To go back to my original point , though - how would you isolate the w m/c , and would a concrete base be beneficial .

 

[colin H]

Sorry - just to correct myself . ive had a look under the floor , and the joists are supported halfway across by brickwork - so the span would be 1.5m I suppose

 

[Richard C]

Sorry - just to correct myself . ive had a look under the floor , and the joists are supported halfway across by brickwork - so the span would be 1.5m I suppose

Well that does make a rather significant difference No criticism intended & for the benefit of others who will see this thread, it’s really very important you get this sort of detail correct as it does make a huge difference. You will be more than OK replacing the existing boards with a 22mm WBP ply base but, at a 1.5m joist span, I would say you’d probably be OK with a decent 6mm tile backer board over the existing floorboards but it's important it's correctly laid.

Regards the washing m/c, is it fully integrated or free standing "on view"?

 

[colin H]

Yeah , I did think the floor felt pretty rigid - now I know why !

The w m/c will be free standing !

 

[Richard C]

Not really sure how practical a concrete base would be or how you would construct it around the joists & up to floor level. I would make sure the feet are positioned directly over he joists or over 4 x 2 noggins. You could make a separate section of ply floor but as it will be fixed to the joists, not sure how effective it would be. You could try something like this; http://www.vibrationsolution.com/ or an anti-vibration mat.

 

[colin H]

Thanks Richard - some interesting ideas there . I like the look of the anti - vibration pads .
I`ll have a think about it , and let you know how I get on .

 

[colin H]

Also , you mentioned tile backer boards . Im thinking of laying electrical matting under the tiles . Are the insulated ones any good - if so , can you reccomend one , please .

 

[Richard C]

I'm assuming this is a suspended ground floor? An insulation board http://www.marmox4u.co.uk/marmox_insulation.php under the heater mat will help with response time (from switch on) & efficiency but without any form of insulation in the void under the floor, heat loss is still going to be significant. Ideally you need to install some rigid foam insulation (e.g. Celotex) between the joists & in close contact with the floor above.

Personally, I question the logic of installing UFH in a kitchen. They tend to be pretty warm places & I know a couple of people that went to all the expense of fitting it & leave it switched off most of the time because it just makes the kitchen too hot; electric UFH is not exactly cheap to run either.

 

[joe-90]

Dunno why you don't just sand and paint your floorboards. Much friendlier feeling than tiles.