What is your preferred method?

[Old Mod]

But you’re left with a ply wood to tile on to which means to meet the grade the ply wood you’re suggesting would have to be SP101 or FG1 or at least the top layer would need to be.

I ALWAYS use an antifracture Mat.

 

[Waluigi]

Regardless of the anti fracture mat, you’re still bonding to ply wood. If it’s general purpose ply then we’re talking about a thin veneered, poorly glued ply which is why I brought up SP101/FG1 or any other Indonesian Ply that might meet flooring grade.

 

[Old Mod]

Well that goes back to my original argument doesn’t it, ply is not a good substrate, period, even if it is overlaid by cement board, jackoboard, whatever board. It’s just poor.
It’s totally unstable.
But the best way to ensure longevity is to prevent deflection, and with ply, the best way is to use two layers.
If there’s no deflection it reduces the risk of it debonding ten fold.
Single layer ply still has deflection to an extent, that’s why it’s good practice to use an alternative, especially one that is inert.
Do you know, I’m sure there’s a couple of products out there that fit the bill.

 

[Old Mod]

I’m sure this must be a similar situation as the choice of using push fit or brass fittings.
We all know you can use push fit, but it’s not always best practice is it.

 

[Waluigi]

I think there are weaknesses in all methods and certain risks, possibly some methods carry slightly less risks.
I do take your points and am just playing devils advocate.

To an extent yes removing the ply wood from the floor entirely is a good idea. Replacing it with an inert board is also a good idea. The fact that these boards have a lot of joints is a negative for the system vs the large board size of ply wood.

The 12mm boards doubled up might be a good idea for strength but with general purpose ply it has a weak spot in the top veneer which anti fracture matting won’t stop. General purpose ply onto joists and then overboarding/glued and screwed does reduce the risk of the crappy veneer pulling away due to the mechanical fixings.

We can go around in circles all day with each method.

With regards to the whole push fit Plumbing debate. The same Plumbers who suggest that Push fit fittings are the work of the devil, also recommend Stuart Turner Pumps, which have OEM fittings on them made by John Guest (speedfit) it catches every Plumber out when the debate arises.

 

[Waluigi]

This made me chuckle though

Goodnight everyone

(The adverts appear before you log in)

 

[Old Mod]

I’m no plumber, and basically don’t have a clue what you’re on about.
I just know the debate exists.
And the level of my knowledge is only on the fact that a soldered joint is far more reliable when you no longer have access to said joint.

And it doesn’t matter that inert boards have more joints than a single piece of ply, which to be fair is a rarity, it’s designed for the job, ply is NOT!

 

[Boggs]

The introduction of push fit plumbing systems is the reason plumbing has been devalued as a trade, I will only use it if it’s temporary.

I worked on a job years back and the tilers overlayed floor boards in a big bathroom with anti fracture mat and layed travertine over the top, that didn’t last long.

In most cases bathroom floors are in good condition so don’t need to be taken up and I won’t charge for unnecessary work.

For me screed floors get anti fracture mat, suspended timber I use chipboard, glued on the joists and tongue and grooves, and 6mm Hardie with S2 adhesive between the layers and tiles.

It works for me and I have not had any problems in many years of doing so.

 

[Waluigi]

Which shower pump do you use, Boggs?

 

[Boggs]

We all know they come with pushfit fittings, as do Aqualisa Quartz showers etc.
If these fail it’s not coming back to me, that’s the problem of the manufacturer under their warranty.
If a fitting fails under a floor and floods a house that becomes my problem.

 

[Waluigi]

Understood- shower pumps or processors aren’t temporary though. The house I’m working in at the moment has I beams on each floor. There are holes along each beam that you knock out with a hammer for services. In this instance push fit or press fit is the only option to get pipes through as notching isn’t permitted. I do agree though, it does devalue our trade.

Trust me though, if an OEM fitting fails on a shower unit, it will come back to you in the same way if a fitting fails under a floor

 

[Boggs]

In cases like I beams or metal web joists there is not a choice so I will use it there, but it allows you to get from point to point with minimal fittings.
But for altering existing copper pipe work I much prefer the old well tested way, it’s no slower really, even on rad alterations, I haven’t drained a heating system in years and solder on the pipework with a cork and carrot.

 

[Waluigi]

Absolutely I prefer end feed too.

Yes I bung open vented systems too. Amazing that there are still people out there who don’t know about it.

 

[Unused Account 1]

The thicker the ply the better ,then ditra,everyones own choice ,as long as they all work

 

[Lakey]

Thanks for the input fellas
I thought that this would be a mine field.....and I think I've been proven right!
So I thought I would give the 22mm NMP a go as what I will spending in additional product I will be saving in labour.
However it seems like the stuff is harder to come by than Rocking Horse......(you get the picture)
I've managed to find a supplier so we'll see how it goes.