All,

I have created a timber 4 X 2 plinth to put my quadrant (1000 x 800) stone resin shower tray on. I have 18mm WBP ply on the top.

The manufacturer's instructions say to bed the tray into a sand and cement mix. I have a couple of questions regarding the best way to install this tray.

1) Should I treat the 18mm ply with PVA before I put my sand and cement mix on it? I seem to read conflicting stories on the use of PVA. Would it prevent the sand and cement mix adhering to the ply correctly? I've also read that PVA should be added to the mortar mix?

2) The stone resin tray is amazingly heavy and I have been trying to think how the best way of getting this tray on to the plinth once I have the sand and cement mix down. There is no obvious way I can think to lower the tray down vertically onto the platform (so as not to move the sand and cement mix) as there is little way of supporting the tray physically. If I get it 3/4 on and then slide it, it will just move all the sand and cement underneath. Has anyone any good recommendations for the best way to lower it down onto the plinth?

Thanks in advance,

Daz

One for the plumbers amongst us I think

dont slide the tray,the cement will just gather.always try it dry first just to make sure it fits etc.i have been known to lay the cement (make sure its not to dry),pop a few ice cubes down (make a few small icecube size channels in the cement).the tray slides on the ice,ice melts and water just mixes with cement.due to weight dont worry if cubes crush,tray will still slide.moved hot tubs in small spaces like this,you dont need an army of extra hands for the job

i would screw 6mm cement sheet to the ply dont use pva (if moisture gets to it it will return to liquid and fail) usa an acrylic primer and yes mix with render hope this helps

Is this the type of tray you mean?

Originally Posted by jay

i would screw 6mm cement sheet to the ply dont use pva (if moisture gets to it it will return to liquid and fail) usa an acrylic primer and yes mix with render hope this helps

Thanks. Can you clarify what you mean by Render? What does the acrylic primer do?

I was thinking of using cement sheet as I have some Hardie backer board left over from using it for the floor. I haven't got enough to do cover the ply in one but can cover it in two pieces. Could I just then mix sand and cement and put it on top of this?

Originally Posted by Dave Ramsden

Is this the type of tray you mean?

Well mine's an offset quadrant shower tray. Mine will be raised and I can't tell from looking at a picture what the material composition is but mine's stone based.

Originally Posted by jolly fix

dont slide the tray,the cement will just gather.always try it dry first just to make sure it fits etc.i have been known to lay the cement (make sure its not to dry),pop a few ice cubes down (make a few small icecube size channels in the cement).the tray slides on the ice,ice melts and water just mixes with cement.due to weight dont worry if cubes crush,tray will still slide.moved hot tubs in small spaces like this,you dont need an army of extra hands for the job

Thanks! That's an interesting idea to use! Don't think I'd have ever thought of that one, but might be worth considering.

Originally Posted by jolly fix

dont slide the tray,the cement will just gather.always try it dry first just to make sure it fits etc.i have been known to lay the cement (make sure its not to dry),pop a few ice cubes down (make a few small icecube size channels in the cement).the tray slides on the ice,ice melts and water just mixes with cement.due to weight dont worry if cubes crush,tray will still slide.moved hot tubs in small spaces like this,you dont need an army of extra hands for the job

above is for tray into alcove,not open setting as in daves pic,for that i would just lay it down on thin cement bed

Originally Posted by jolly fix

above is for tray into alcove,not open setting as in daves pic,for that i would just lay it down on thin cement bed

Thats what we did

personally I prefer a bed of flexi addy to cement, but love the ice cube idea

Originally Posted by DazJWood

Thanks. Can you clarify what you mean by Render? What does the acrylic primer do?

I was thinking of using cement sheet as I have some Hardie backer board left over from using it for the floor. I haven't got enough to do cover the ply in one but can cover it in two pieces. Could I just then mix sand and cement and put it on top of this?

cement sheet in pieces will do
render is your sand cement mix
acrylic primer is a primer but it will improve the sand and cement mix (make it more sticky)

Prime the boad with acrylic primer as already mentioned. I use a glass suction pad on the tray to help lower it into place as i dont keep ice cubed in my tool box. If its a non-slip base they can be tricky as the suckers dont stick! Especially if they are offest quads as the waste hole isnt much help when lifting either.

I have nt tried flexi addy as i dont want it to move and i tend to stick to manufacturers instructions. However what ever you use they do tend to stay in place under their own weight.

if on a new build site etc,then ill visit shop by bag of ice £1,50.most jobs ive done clients have ice in fridge freezer..only use 4-6 cubes.

Originally Posted by jolly fix

if on a new build site etc,then ill visit shop by bag of ice £1,50.most jobs ive done clients have ice in fridge freezer..only use 4-6 cubes.

Its a novel idea, im not knocking it. Cant say ive ever really struggled to get one in

One thing i will add, if your using a high flow waste make sure you cut out enough space around the waste hole to connect the pipe as they tend to foul the underside of the board

99%of the time just lay the tray down onto the cement.just the odd time when very large tray ,very tight space and no extra hands to help.

ice -cubes this will wash any cement in the mix out!!! make a proper mix of sticky morter-up then prime both surfaces to be stuck toghether annd applie morta to the bottome surface and lower shower tray on to it, simples!! then you dont look like a loony off some kids TVprgm

been a stonemason for over30yrs never found that a little bit of water washed cement out.again i 99%of time just lay/lower the tray down onto the mix,but on a few jobs due to walls (purpose made in built seats),you cant lay tray down but have to slide it into position,you can angle it a bit to cover most of the mix at times but when you slide mix just gathers one end,covers side sealant etc.....oh hate to admit it but have been on a few kids tv shows,no i wasnt building an igloo.

Originally Posted by jolly fix

been a stonemason for over30yrs never found that a little bit of water washed cement out.again i 99%of time just lay/lower the tray down onto the mix,but on a few jobs due to walls (purpose made in built seats),you cant lay tray down but have to slide it into position,you can angle it a bit to cover most of the mix at times but when you slide mix just gathers one end,covers side sealant etc.....oh hate to admit it but have been on a few kids tv shows,no i wasnt building an igloo.

well you try mixing some mortar on a board then drop an ice cube in the centre and leav in the sun as a test and the water will wash the OPE out of the sand and you will have a weak point !! you will tell us next to lay tiles on sugar cubes and poreon tea!!does it not tell you that if this was a tryed and tested way of working that is would be taught in all tech-collages around the country

im just saying that this has worked for me.just about 4 cubes (they will crush) give the tray slight tap down when in place it mixes ,like concrete tap and water comes to surface etc air bubbles out etc......under tray not in the sun,they dont teach this at tech,they dont teach alot of things in the real world at tech,i was tought this by an ole stonemason when i was an apprentice.handy for getting crane stropes of large stone when lowerd into place,ive never had any probs.not saying its the best way etc.only used it the odd time..

ok jolly ill jogg on at this point and leave you to your beliefs!!!

Originally Posted by gooner59

ice -cubes this will wash any cement in the mix out!!! make a proper mix of sticky morter-up then prime both surfaces to be stuck toghether annd applie morta to the bottome surface and lower shower tray on to it, simples!! then you dont look like a loony off some kids TVprgm

Is that Latin Gooner?

I personally think it is a good tip... thanks jolly fix..


Gooner.. 4 ice cubes ain't gunna break a bed of sand cement.... little tricks like this can be life savers when trying to slide a tray into situ..

yes it will it will weaken the mix in the areas around the edge,if you are just bedding around the edge! IMO

It shouldn't be bedded just around the edge though....IMO.

Originally Posted by gooner59

yes it will it will weaken the mix in the areas around the edge,if you are just bedding around the edge! IMO

but in this instance, even if the mix is weakened slightly (and i don't think it would really) the bed of pug is there to offer an even support for the tray not structural strength

OK GUYs AS I SAID TO JOLLY ill jog on you do it your way and ill do it mine, but if you were on one of my jobs you would do it my way or no way!!

Originally Posted by Dave

It shouldn't be bedded just around the edge though....IMO.

I think Gooners a Dot and Dabber

ive seen this done before and it does work, seems to be a stonemasons trick

[ame=http://www.youtube.com/watch?v=pi_tZsH5pmg]YouTube - ice cube - You Can Do It (ft. Mack 10 & - Greatest Hits[/ame] a tun for friday night