Issue with Shower Tray - Is builder culpable?

Burtbot

We had some major reno's done last year, one of which was a complete bathroom refurb. 

I am convinced there is an issue with how they installed the timber frame for the shower tray, as ever since it was installed one part of the tray sinks down when you step on it - like this one bit is hollow underneath. This had caused the tray to sink down at this point, which is now causing a crack on the edge of this area. I have mentioned it to the builder who has claimed it's a manufacturers fault. He said that his men "would have installed it to the manufacturers instructions". He is blaming movement of the house. 

However, it turns out when installed the tray they should have put mortar underneath the tray. The builder admitted they didn't do this but used a timber frame and his builder has been building these for 15 years etc etc. 

My question is - if they have admitted that mortar wasn't installed underneath the tray after having said to me that they would have followed the instructions, does that automatically make them culpable? I just want the issue fixed as it's only going to get worse. 

For info - the shower tray is really heavy and very good quality - so thats not the issue. 

Thanks all! 

ThisIsWeird

Almost certainly it's an installation issue, so the builder will be culpable.
The thin mortar bed is to ensure the whole bottom surface of the tray is fully and equally supported. In your case, either the timber frame is moving (relatively unlikely, as they'd have got that bit right) or the lack of 'bed means there's an unsupported void, and that's why it's flexing.
Over time, the chance of the tray cracking or just leaking due to this movement is extremely high.

I have that style of tray here ready to fit. Solid and heavy, it has a decorative 'skin' and is filled with what looks like a stone resin. But the 'fill' is not perfect, and not 100% flat, and that's quite normal. It won't be an issue provided a mortar bed is first laid, as this will fill any small gaps, and support the whole tray evenly.

It's also not a case of a timber frame or a mortar bed; mine will have both. The frame will be topped with ply or waterproof chipboard, and the mortar bed laid on this.

What to do? You clearly have a case. They clearly are liable. Back this up with an email to the manufacturer; "My builder didn't lay it on a bed or mortar and says this is ok. It's now flexing - what's the cause...?!", and send him the answer. Tell him it must be sorted, as it will otherwise fail. If they refuse, you tell them you'll get someone else to do it, and send them the bill. Followed by a SCC claim if needed. This should be an open and shut case.
(If it goes that far, then ensure plenty photos are taken when the new plumber lifts the tray.)

Do you have LP on your insurance? It's made for this sort of stuff.

Burtbot

ThisIsWeird said:

Almost certainly it's an installation issue, so the builder will be culpable.
The thin mortar bed is to ensure the whole bottom surface of the tray is fully and equally supported. In your case, either the timber frame is moving (relatively unlikely, as they'd have got that bit right) or the lack of 'bed means there's an unsupported void, and that's why it's flexing.
Over time, the chance of the tray cracking or just leaking due to this movement is extremely high.

I have that style of tray here ready to fit. Solid and heavy, it has a decorative 'skin' and is filled with what looks like a stone resin. But the 'fill' is not perfect, and not 100% flat, and that's quite normal. It won't be an issue provided a mortar bed is first laid, as this will fill any small gaps, and support the whole tray evenly.

It's also not a case of a timber frame or a mortar bed; mine will have both. The frame will be topped with ply or waterproof chipboard, and the mortar bed laid on this.

What to do? You clearly have a case. They clearly are liable. Back this up with an email to the manufacturer; "My builder didn't lay it on a bed or mortar and says this is ok. It's now flexing - what's the cause...?!", and send him the answer. Tell him it must be sorted, as it will otherwise fail. If they refuse, you tell them you'll get someone else to do it, and send them the bill. Followed by a SCC claim if needed. This should be an open and shut case.
(If it goes that far, then ensure plenty photos are taken when the new plumber lifts the tray.)

Do you have LP on your insurance? It's made for this sort of stuff.

This is so so helpful! Thank you Completely confirms what I expected. 

They have agreed to fix the cracks, which apparently will take 4 days. So I am going to suggest that instead of them fixing the cracks, in those 4 days they replace the tray. We do have LP, so if it comes to that (which I really hope it doesn't) then we have that as back up. 

bob_a_builder

Fix the cracks ?

ThisIsWeird

As you suspect, Burtbot, fixing the cracks is not a solution.

I can understand their reluctance to sort this - it could be a major disruption if they cannot 'slip' the tray out from under the tiling, for example. But, tough - their problem, and so far it's been a poor response by them.

When they do agree to fix it, I'm afraid you'll need to keep an eye on the job

Burtbot

Yes, fix the cracks...Which isn't going to help in the long run of course, as the cracks are happening do to the stress of the flexing tray. 

I suspect the job will be a pain, as they'll need to remove tiles and whatnot. He did though tell us before the if we wanted to pay them to do this it would take about 3 days. So, should be covered in the time they've already allocated to fix the cracks. 

I have another question. He keeps blaming movement of the house, saying that's what has caused this. Would it not stand to reason if the movement were so bad to create a voided area under the tray, we would see evidence of this elsewhere? Like cracks on the ceiling? 

ThisIsWeird

Movement of the house... Wow.  He cannot possibly mean that in a literal sense.

I wonder if he means movement in the floor, as in the joists aren't beefy enough? But, if so, this should have been ID'd at the time of installation, and additions made to strengthen it - extra timber noggins, or 'sistered' joists, for example. You know, what I did - as a DIYer - when I fitted our shower.

There is no excuse. It hasn't been done properly. We obviously don't know if it's only a matter of lack of 'bed', or whether the supporting frame also needed beefing up first. IE, is there movement in both.

RonRamsgate

 From post 1. "One part or the tray sinks down when stepped on", thats wrong but great to see your looking for more information.

First reach out is do you have the A4 leaflet stating the installation instructions. That will give the manufactures guidelines or even more. If you do not have the installation instructions they are usually available online.
There are usually generic. Let us see the instillation document 

Some trays just need bonding down (glue) to a suitable surface others need the mortar mix. The mortar mix helps the unevenness of the shower tray base and other considerations.
All Shower trays need to be checked before they are fitted, they can be rejected if they are warped (happens in storage/transportation) they leave the factory door correct.
Every installer will have a long spirit level or strait edge to check the base  run out and then work out the best practice installation process. 

Edit, the house is not moving but have they done other structural work like knocking down walls. 

Sorry to hear your having problems, hope you get it sorted out soon 

Burtbot

 RonRamsgate said:

 From post 1. "One part or the tray sinks down when stepped on", thats wrong but great to see your looking for more information.

First reach out is do you have the A4 leaflet stating the installation instructions. That will give the manufactures guidelines or even more. If you do not have the installation instructions they are usually available online.
There are usually generic. Let us see the instillation document 

Some trays just need bonding down (glue) to a suitable surface others need the mortar mix. The mortar mix helps the unevenness of the shower tray base and other considerations.
All Shower trays need to be checked before they are fitted, they can be rejected if they are warped (happens in storage/transportation) they leave the factory door correct.
Every installer will have a long spirit level or strait edge to check the base  run out and then work out the best practice installation process. 

Edit, the house is not moving but have they done other structural work like knocking down walls. 

Sorry to hear your having problems, hope you get it sorted out soon 

Thank you! 

So I do have the instructions, and they do say the following;

"So that the tray is bedded completely level the tray area has to be FULLY COVERED with an 8mm minimum thickness of weak cement mix (Fig 3). The minimum thickness of mortar at the lowest point should be 5mm after the tray has been levelled. Check that the top of the tray is level (Fig 4).
Ensure that the entire base of the tray is fully supported as the base of the tray may not be entirely level. This is due to the manufacturing process. Note the base of the tray has a built-in fall to allow for drainage."

He admitted they only used a timber frame. 

They did knock down a wall underneath the bathroom, so maybe this could have caused movement? But then, would that not be more reason to use mortar if that risk is there? 

Burtbot

 From post 1. "One part or the tray sinks down when stepped on", thats wrong but great to see your looking for more information. - why is this bit wrong?

There's an empty space under one part of the tray, and when you stand on it it sinks down. This is where the crack is appearing. The second comment described as a void, which is exactly what it is.

ThisIsWeird

If the removal of a downstairs wall is causing so much movement that the tray has failed, then you have much bigger issues :-)

The tray needs a flat platform to sit on that doesn't flex, and then a bed of mortar is applied in order to take up any gaps,  discrepancies or unevenness in the tray's underside. These are two separate requirements, and both are needed. If you don't have a flat unflexing base on which to apply the mortar, then you don't go any further until you do. 

And it should be obvious if you do not have this at the time, and - if you do not - you beef it all up until you do. Then you add the mortar and move on.

As I said, we don't yet know whether the flex in the tray is due to 'just' a lack of gap-filling mortar support, or whether the platform made for it is inadequate and is moving. I hope it's just the former, since they acknowledge they haven't done this bit, and also it'll be relatively easy to sort (once the tray is removed...). But it's worrying that they tried to blame 'movement'. It's either an excuse, and there isn't any (it just needs the mortar bed), or they are actually aware of 'movement'. For this, they need to find a solution, which should not be hard.

So, worth the question; "You said there was 'house movement'. What do you mean by this?"  And if they confirm that the platform is moving, "How are you going to sort it...".

Good luck