How to install a new inset bath in a pre-existing frame?

[crisis]

Hello friends, 

I successfully removed the concrete bed under the old bath , without damaging the slab, with the help of some workshop members' advice. I'm back for some help with trouble shooting how to install the new bath. The pics attached show the measurements of the existing bath frame which I was hoping to re-use. I have a bath chosen that fits but I am not sure how to get it into the frame. I can't drop it in because of the tap fittings. There is not enough space to angle it in from the far end. There is not enough room to angle the far lip of the bath under the tap points and then drop it in either. The conclusion I have come to is that I need to remove the whole front side of the frame, slide the new bath in onto a fresh cement base and then immediately position a new, pre-prepared frame on the front side before filling the bath (in this case weighting it down with buckets of water). The bath I want to put in is 1700mm long x 700mm wide at the top. The tub part is 570mm wide Thoughts? Advice? Things I haven't thought about?

Anyone worried about waterproofing I will install waterproof angles around the three sides prior to installing the bath, and pre-install an angle on the pre-prepared outward facing replacement frame. 

Thanks friends

.

[Nailbag]

Once its plumbed in and siliconed its not going anywhere @crisis 

Nailbag

[crisis]

Hello, thought I’d reply with an update to help future readers looking for advice.  I shimmed and siliconed but before this I also lifted bath a smidge and put a layer of silicone between bath and mortar bed. This stopped any slight movement. Included a pic not that it shows you much. The walls and frame have also been prepped for waterproofing

[JacobZ]

Hi @crisis,

Things look to be coming along nicely.

I can't wait to see everything once it has been completed.

Thanks for the update.

Jacob

[pollywog]

Hi Crisis,

Just wondering how this went for tiling as I’m in the middle of a similar project. Did you leave a gap for the tiling to run under the bath lip on the dwarf wall and if so did it have to be exact allowing for tile thickness and adhesive?

Any update would be appreciated.

[crisis]

Hi pollywog,

The tiling hasn’t happened yet but no I didn’t leave a gap under the bath lip. You want the bath to be resting as completely on the frame as possible and then any gap needs to be filled and siliconed. Not sure of your situation and I am not an expert but my understanding is that if you left a gap and tiled under the lip this would compromise waterproofing both from water seeping in over time through grout but also potentially interfering with the fit of the angles around bath frame. Also not sure tiles could withstand weight of a filled bath over time without cracking and creating more entry points for water.

[pollywog]

Brilliant, thanks for the response. That makes sense and makes it easier it’s just that the diagram from my baths instructions seems to suggest tile underneath (I attached as reference) but it’s not very clear.

Thanks again and all the best with the rest of your renovations.

 

[MitchellMc]

Just to clarify @pollywog, the bath edge shouldn’t sit directly on the brick or stud frame. Over the bricks or studs you first need to apply a waterproof membrane that runs up the vertical face and continues across the top of the hob. At the back edge, there should also be a water stop installed, usually an aluminium angle, which sits under the lip of the bath. Its job is to stop any water that gets under the bath lip from tracking back into the frame and instead direct it back onto the membrane.

Once the membrane is done, the tiles are laid up the face of the hob and across the top. The bath then sits on top of the tiled surface, not directly on the frame. After the bath is in place, you seal the joint between the bath lip and the top tile with silicone. The side support shown in the instructions is there to give additional rigidity and support to the bath edge once it’s sitting on the tiled, waterproofed surface.

The reason for doing it this way is that if the bath were placed directly on the frame and only sealed at the tile edge, any failure in the silicone would allow water straight into the frame and behind the bath. Having the membrane and tiles beneath the bath edge, along with the water stop, gives you proper waterproofing protection and greatly reduces the risk of future issues.

All the best with the rest of your renovations, and feel free to ask if anything else comes up.

Mitchell

[pollywog]

Thanks for that detailed response Mitchell. That’s how I interpreted it from my instructions and diagram, but on the other side of the bath against the stud wall,  the tiles come down and sit over the bath lip meaning the bath would need to be installed before tiling. I guess this means I’ll need my tiler in before bath install to tile dwarf wall and then install bath and have him back to tile down opposite wall over bath edge.

Does this sound right? Or am I missing something?

Thanks in advance.