Injecting support for a shower tray

Hi - my plumber has just installed a shower tray, and it would be very difficult to remove. However, the tray is not very well supported., and flexes when stood on. It was supported with mortar, but only in a few areas (for some reason), and these blobs of mortar have not stuck in place so they can be pushed around with a stick...
However, I can get access with a hose to the cavity under the fibreglass tray. Can anyone suggest some sort of filler I can pump into the void, which will set hard enough to support the tray well? I'm concerned standard expanding foram may not be up to the job...
Cheers,
Ben
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The correct solution would be to ask the plumber to come back and fit the tray properly. If it's difficult to remove, that's his problem. If he breaks it getting it out, that's also his problem.
It should be bedded according to the manufacturer's instructions and that usually involves support for the whole base. If you do something now that turns out to be unsatisfactory and the tray cracks in a few weeks or months you will have no real come-back.
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Unfortunately the manufactures instructions were in no language known to mankind - multiple translations had been involved I think. If it is damaged, it becomes my problem, as it was very hard to source, and will be extremely hard to replace.
I had assumed they would do the following however:
Put tray upside down Fill with mortar Place pedestal on top Wait to dry Up end whole lot Done
Hence the whole cavity is filled. It seems this was not done...It is difficult, 'cos my plumber is very nice and claims it will be fine, but I'm don't really share his confidence...
Ben
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barkerben wrote:

Did the plumber supply the tray? If he did, the instructions and sourcing a replacement are still his problem.
Owain
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Unfortunately not - it is a non-standard size, so I had to source it. The instructions leave something to be desired - like english that makes sense :-)
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barkerben wrote:

There was a case, IIRC involving an ICI pesticice, that held that instructions were part of the product and faulty instructions meant that the product itself could be regarded as faulty.
If you bought the tray as a consumer I think you could expect it to come with sufficient instructions that it could be fitted by a competent DIYer or professional. Therefore you may have recourse against the retailer if you can show your plumber followed the inadequate instructions and it all went wrong.
Owain
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Well, as of yet nothing is broken...I hope to manage not to break anything by suppotying the trsy, one way or the other, before it gets much use. To the best of my knowledge the plumber is a good bloke with an excellent reputation, so fingers crossed...
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Oh dear.

The normal way is to lay a bed of relatively dry mortar over the whole area and to bed the tray down onto it

Unfortunately being nice is going to address the issue. Perhaps find a similar looking tray and look at the instructions for that/?
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On Sat, 27 Oct 2007 06:24:51 -0700, barkerben wrote:

=================================I don't think this would be a good way to get a full mortar base as the mortar would be so heavy that it would probably fall out when you turned the tray the right way up.
On the other hand this would be a good way of filling the entire cavity (allowing space for necessary access holes) with expanding foam since you could over-fill and slice off the surplus when fully cured. It would be best to leave the foam slightly 'proud' if you choose this method.
Cic.
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On Sat, 27 Oct 2007 06:05:12 -0700, barkerben

Standard expanding foam will be more than strong enough if the void is completely filled. However, the problem will be getting the right amount in. It continues to expand for about 20 mins and if too much is put in place with no expansion outlet it will be more than strong enough to push a ceramic shower tray up out of its mountings. You would have to do it in installments putting a layer of foam filling the space vertically but not horizontally, leaving it to set (and expand horizontally, and repeating the process. Simply squirting a pile of foam through a hole will almost certainly lead to either not enough foam going in or too much with the consequent risk of damage.
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Peter Parry.
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There is a cavity approx. 10cm high, with a hole for the waste through which a hose can be put. I was thinking that I could put an extension hose on my foam cylinder, then fill from the back of the shower tray, working forwards towards my hole. Hopefully the stuff is runny enough that it will fill sideways if it finds above is blocked, with the eventual release point being the hole I have poked my hose through...?
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It will roughly double in size, mostly after it's too stiff to be forced out of the hole. You'd probably end up with a domed bottomed shower tray. (Do have a digital camera handy so you can put the pictures up on a website;-)
I think you can do this with expanding foam, but you are going to need better access and visibility underneath to control the quantity.
Have a read of http://www.diyfaq.org.uk/humour.html#foam
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Andrew Gabriel
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On 27 Oct, 15:16, snipped-for-privacy@cucumber.demon.co.uk (Andrew Gabriel) wrote:

I suppose the only way of ensuring full support then would be to use something extremely fluid and non-expanding. Seal around the hose entry point and simply fill up the void, then wait for it to go off. Any ideas of such a material? We use something like that for sealing the bottom of on-street equipment, but unsure what it is made of!
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On 27 Oct 2007 14:16:04 GMT, Andrew Gabriel wrote:

That's what it says on the tin, I don't believe it. Quadruple from the inital size a few seconds after leaving the tube is more like it, at least with the DIY stuff.
There is in effect a double expansion, an inital one lasting say 30s to a minute, from when the stuff leaves the tube. This inital expansion is roughly double from the size a few seconds after leaving tube. Then a much slower and longer one (20 mins or so) which doubles the volume again.
Also be aware that the stuff sticks to anything and everything, instantly. Vegetable oil is a good release/cleaning agent. I'll certainly cover my hands with veg oil next time I ever use the stuff.

Or get one of the foams that just does the initial 30s - 1min x2 expansion. The window fitters last years had something that did just that, far easier to judge how much to squirt in. Another thought is to use some form of mould to force the foam up to the base of the tray but have a gap for over expansion and do it in stages working forward, if you have the access of course. For a mould I'm thinking of some thin card rolled into a 4 to 6" dia cylinder.
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I had been thinking of getting a canister and putting a section of hose on the front, approx 1m long, so that I could deposit the foam in the correct places. The question is whether the pressure would be enough for this extension tube to work...
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On Sat, 27 Oct 2007 09:19:03 -0700, barkerben wrote:

If by "hose" you mean 1/2" garden hose probably not but a narrow bore tube probably. Just don't use anything you want to use again...
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Cheers snipped-for-privacy@howhill.com
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Peter Parry wrote:

There are low expansion foams available.
For example <http://www.toolstation.com/search.html?searchstrf044>
I haven't tried it myself but help might avoid an oozing mess or expansion damage!
HTH
Steve
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barkerben wrote:

Usually with fibreglass trays they have support brackets or feet that carry the tray and take the strain. They do not eliminate all movement however.

One usually uses mortar for stone resin trays - these are preformed concrete trays with a resin cap - a totally different proposition from what you have fitted.

Dabs of foam under the most bouncy bits would probably do what you want quite nicely. Just take care not to go mad with the filling!
--
Cheers,

John.

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Who sourced the tray?
If the plumber's choice he will need to fix at HIS expense.

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I sourced it - the only one I could find in that size. However, if it was not fitted correctly, then I would still seem to have somne comeback. Hmmm...
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