# Forum Home Renovation Bathrooms  Fitting a bath? I know, I know.....

## anawanahuanana

I know what you're all probably going to say, but I have to ask the question, as it could save me some bother and time. 
I know that when fitting a bath, it is supposed to sit on a bed of mortar, but is it acceptable to sit it on some decent size timber crossmembers? I only as ask as that is how my old bath was mounted (see pictures). 
I have to assume it was fitted by a competent and licenced tradesperson, so is this an alternative? 
I have to admit, I never got in the bath and thought it felt anything other than completely stable. 
Comments please.......

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## rat52

The original idea of bedding baths in mortar was because they were enamel and very heavy also it removed the drumming if you dropped the soap. 
I was told buy a plumber it also reduced the risk of the enamel chipping. 
I have seen them done on bearers with insulation under and around to keep the water hot. 
__________________________________________________  ______________ 
Don't force it, use a bigger hammer.

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## peter_sm

Acrylic bath needs to go on a mortar bed to stop you cracking it when walking. 
A pressed steel/ glazed bath needs a frame that fully supports all around, and insulation wrapped around to keep the heat in. 
The old cast iron baths could be held up by frame also, but not necessarily need any insulation as they held the heat.

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## mic-d

And if you put an acrylic bath on space filling foam, you;ll find it will void most warranties... 
CHeers
Michael

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## anawanahuanana

Thanks for your answers guys.
So I guess my easy way out of supporting the bath at the base on 4 bearers of 35x70 pine is a no no then. Better get some bags of mortar.... 
As an aside, everyone talks about bath warranties. I've never heard of a bath failing. Does this happen very often? I guess they hold a lot of water/weight, but they are not exactly a high use item, at least not in my house! 
Thanks again.

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## celeste

Hi all 
I just purchased from bunnings and installed an acrylic bath - the base looks similiar to your photos. The instructions said and I quote. 
" This bath does not need a to be bedded in mortar" 
It's instructions said to place some tile adhesive on the floor and put the bath on that. 
I built a frame as I needed it higher off the ground - waste going out the side wall not into the floor, cemented down some bricks to height and then put some tile adhesive on top, then bedded in the bath. 
Oh and my plumber said, " there is nothing in the plumbers hand book in regards to using the foam"  
Celeste

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## Iain

We just put down a slurry of mortar and dropped it in, a shower/Bath/spa combo that has to put up with my bulk, I like the idea of something solid underneath.

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## nic

I just installed a acrylic bath and at first was a bit skeptical about the whole mortar thing.
Did it anyway and I now understand it's absolutely necessary, give the bath stability and strength.
At least I know that it's not going to go anywhere when the kids jump up and down inside.
You can also fill it up with water to make sure it sets in the mortar correctly 
Nic

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## julianx

most of the acrylic baths I put in these days come with a metal skid frame with adjustable legs, just slide it in to place adjust the legs then frame around it. No mortar needed.

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## Bill_E

I have been installing baths as an apprentice/tradesman and Licensed Plumber for 50 years in Western Australia. Cast iron baths require no bedding, the wall side and end is usually set into the brick wall or studwork and the outside is usually supported on a timber frame or the brick riser. Pressed steel and acrylic baths are usually fixed the same, sometimes in brick construction (Most houses in the West are double brick) a 75x35 timber rail is bolted to the wall to take the wall edge. Bedding of very dry (Damp) 3 in 1 sand and cement bedding is packed under the bath, a dry mix is used because cement shrinks when it sets if it is wet and you get a cracking grinding sound when you walk in the bath. <O :Tongue:  Some acrylic baths have a metal frame and adjustable legs these should be fixed as per manufacturers instructions. <O :Tongue: </O :Tongue:  We have had very good results using space filler foam under acrylic and pressed baths and acrylic spas however baths must by set level and filled with water BEFORE you foam it in otherwise the bath will lift  Bath shouldnt be drained until foam has set, we usually only use a thin bed of foam approx 20mm applied with a long nozzle on a base of Gyprock or hardieflex. <O :Tongue: </O :Tongue:  Bath warranty: We have only ever installed one bath that had a warranty claim and this was unrelated to our installation, it was a manufacturing fault that developed on the side of the bath, there was no warranty issue that the bath was on a Space filler foam bed. The manufacturer inspected the bath and paid us to remove the old bath and reinstall the replacement and said the foam looked like it was a good trick if done the way we do it.

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## anawanahuanana

Before I start, thanks to everyone for their advice so far.  
Well, first problem with the bath installation! After putting villaboard on the frame and plastering all the joins prior to  installing the bath (on a mortar bed by the way!) I went to pick up the final piece in the puzzle. 
The old bath had a "Plumbdinger" on the drain, and so due to limited clearance between the bath bottom and the waste pipe out of the slab (100mm) I planned to use another one. However, they are not long enough for the distance between the waste pipe and bath drain. So, I have a choice of raising the bath by 20mm which gives me just enough room to use a rigid or flexible waste pipe, or digging away at the slab to move the waste outlet close to the drain. I think I'm gonna raise the bath, as it shouldn't be too much effort as I've got a load of 35x75 left in the garage, and I secretly wanted it higher than it is anyway but SWMBO wasn't keen! 
That'll teach me to assume something is available before I actually have it in my hand......
Anyway, onwards and upwards. Literally......... 
As an aside, does anyone have a preference when it comes to tiling the bath box? Tile the whole top and put the bath on the tiles (would be mosaics) or fit the bath and tile around it? 
Cheers! :2thumbsup:

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## julianx

> As an aside, does anyone have a preference when it comes to tiling the bath box? Tile the whole top and put the bath on the tiles (would be mosaics) or fit the bath and tile around it?

  I'm sorry to say I would recomend having no top of bath box at all, they invariably leak. I always frame the bath with enough gap between the frame and the lip of the bath to tuck the vertical sheet and tiles into.
If you must have a top then tile first and try and put some fall away from the bath.

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## Pooran

Just reviving an old thread. 
I plan to replace my old enamel bathtub with a acrylic one. A quick crawl under the house revealed that there are no floor boards under the current tub so how am i supposed to lay a mortar bed if there's no floorboards?

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## davo2310

pooran, why not, after removing your old bath, lay a sheet of fc sheeting on the joists, then you can mud away

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## Pooran

That makes sense Davo but i would have thought mortar would probably be too heavy for a sheet (or 2) of cement sheeting. Ah well I bought extra sheets so at least I know I have a use for them.

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## davo2310

Thants not fibro wall sheeting im talking about, I mean 16mm plus floor sheeting to be precise, wall sheeting will sag if use it.........just making sure we are on the same wave length mate.

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## chuth77

Acrylics(Read Fibreglass) as a rule need mortar to support, not only the base, but the corners also... Some as past posts have mentioned, don't require a bed, but these generally have metal frames, or inbuilt supports on the base, which must be fitted to a flat surface... 
The problem with arylic/fibreglass is its flexing, which when people get in and out of an unsupported bath, flex at the corner which are the weakest points! Over time the fibreglass gets a "cancer" and develops hairline cracks... Warranty call... 
The use of foam filler is an absolute no-no... Read the can... It shouldn't be used in an form in trafficable areas... The foam over time begins to crumble, and then your void is back! Hence why bath warranties are vioded if you use it... If you do have a small void, use a good quality non-acidic silicon to fill it...

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## dean77

Having read this I noticed my acrylic shower bath has a slight cracking/grinding sound, it doesn't seem to move though.  It looks a few years old (just bought house recently) and I can't see any cracks - any idea of how this may affect the life time of the bath? 
Thanks

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## chuth77

If it's not moving substantialy in the base it's probably not too bad. The noise will be because the mortar mix underneath has shrunk, and hasn't adhered to the bath. If it sounds like a bit of grit each time you move,thats what the problem will be...

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