[Closed] MDF or ply for this?

Ply.

I would trust Selco to do the cuts.

I avoid using MDF anywhere near water.

As above, i avoid MDF anywhere where it can absorb water over time, if it's only a small amount and it's going to be visible and locked in then i'd be tempted to get some marine ply as well due to potential condensation/steam delaminating the sheet over time, yes i know marine ply isn't all singing all dancing for this, but it's slightly better than the normal stuff.

Depends on the mdf just as it depends on the ply.
It's what the material is specified for, not the material itself as such.

I'd have thought you should no more use interior-grade mdf as you should interior-grade ply.

I always use Moisture-resistant mdf (the green stuff) over the regular kind as it paints and finishes better ime.
I still wouldn't leave it outside though or have it in a shower.

You can get an mdf that is specifically for exterior applications.
Medite Exterior MDF

Waterproof plaster board?

For structural strength plywood not MDF. Eg half inch ply is a lot stronger than half inch MDF. I don't entirely understand what you are planning to build but as it appears to be a wall then ply is the obvious answer.

Pretty much what kayak said.

The moisture resist and exterior grade MDFs are very good. I made a working, full size replica water wheel out of it. MDF will be much easier to cut and finish than ply. Ply will be stronger but for an interior wall MDF will be strong enough.

As for B&Q they'll only cut what they sell and I'm not sure if they sell any of the good stuff. The saw they have is very good and cuts true. I've always had good cuts from them except for once when the young lad couldn't covert my mm dimensions into cm! We go there in the end but I lost a bit of timber.

Wall is already built but we've changed the shower room a bit and this is what I want to cover (no strength required)

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From the other side
[img] [/img]

Ah basically it's just a bit of boxing in. Yeah MDF is probably better as it is flatter/less likely to twist/more stable than ply.

I don't think that Selco will cut moisture resistant MDF because of greater health risks when cutting it indoors. If you cut it obviously do it outside.

if youre literaly just covering that up, and its in a bathroom, i would go and bother your local Double Glazing/Window/UPVC supplier. you can get all sorts of profiles in basic flat white UPVC.

Aye, I'd go to my local Eurocell for plastic trim, or if you really want to tile, go with TJ's plasterboard suggestion.

As above, you could get a uPVC profile to fit that

That looks about done to me, add it to the "I need to finish that at some point" list. And tackle the next "a couple of hours" task on your list.

That should see you until Christmas at which point the only way of fixing the broken central heating will be to go through those tiles, requiring a new bathroom when you discover one of the joists it's rotten through.

@joshvegas seems to have been in my house! 🙂

Marine ply ...

Definitely not using UPVC.... sorry!
Maybe marine ply then.

Insulated cement tile backer board, might be a bit more expensive but probably easier to cut and tile over?

Given the chrome finish to the shower, how about some stainless sheets of appropriate size?
Not cheap, but far more waterproof then either ply or mdf and should look nice next to the shower.
Aluminium sheet might be cheaper

Some MR MDF and an excuse to buy a router and some bits. Knock yourself out making pretty patterns 🙂

easier to cut and tile over

I'm not tiling.

far more waterproof then either ply or mdf

It's extremely unlikely to get wet as it's outside the shower and facing away from it!

I've actually got some 12mm ply that's long enough but it's a bit old and got a slight bend at one end.
I'm talking myself into mrmdf at the moment.

Find your nearest cladding fabricator and ask them for a piece of alucobond a2 in white, give them the dimensions including the height making sure you hand it correctly then ask them to machine it, rout it and put the bend (external) in.

Take it home then glue it on.

The moisture resist and exterior grade MDFs are very good.

I’m talking myself into mrmdf at the moment.

Having bought tens of thousands of pounds worth of the stuff over the past year, In the world of Covid/Brexit and associated supply line difficulties..... theres some absolute garbage MR-MDF about at the moment. Its green - thats it.

It’s extremely unlikely to get wet as it’s outside the shower and facing away from it!

If it was actually genuine MR stuff and not just something with food colouring in as we seem to be getting at the moment - then its not the issue of being submerged, splashed or whatever - conventional MDF just breaths in moisture from damp atmospheres in kitchens and bathrooms - it soaks in the moist air - expands - but doesnt then contract again when it dries. So conventional MDF will swell over time in moist air. MR-MDF is designed specifically for that application - environments with moist air not direct contact with water. But I'd not trust anything sold as MR to be what it claims to be at present.

I don’t think that Selco will cut moisture resistant MDF because of greater health risks when cutting it indoors

I actually thought it was the other way around? That MR mdf had no formaldehyde in it and so was less bad, than regular.
I expect I'm wrong.
I certainly find cutting regular mdf far more minging.

MR does seem to kick up a lot less dust. It also needs less finishing and sanding afterwards.

Mdf of any sort in shower room will blow when it gets wet and it will.

The pink fire rated stuff with what appears to be salt impregnated in it might work. Cheap ply will also delaminate as someone posted above there is some crap around 12mm ply is full of pocket voids around by me And some 25mm is coming out at 22mm and end and 26 the other 🙂
I would plasterboard/cementboard it cornerbead and skim.

Good luck dude

Looking at the photo I cannot imagine a scenario where covering that in MDF or ply will ever look finished and not just like some MDF/ply fitted and painted to hide that it's not finished.*

Plaster and skim , uPVC trim , wet wall etc etc.

* Based on inheriting a bunch of painted ply and MDF art installations in my current house from the previous bodger that thought it was a good solution to anything.

If you go to B&Q you can get window boards. These are designed to be used for window sills or patio door sills which experience as much moisture as your shower enclosure. They're 25mm thick, rounded at one edge if you'd like that detail and come in primed MDF, pine and oak. You might be able to get a single piece wide enough to cut and do both sides.

Thanks for all the info guys..... Great pointers.
👍

I'll be giving this more thought.
It been like that for 2 years already and my eldest daughter (who's room it is) is in London for another 8 months so there's no great rush!

Blue grit coat and plaster directly on to it? Our plasterer reckons you could plaster over glass with it.

fibreglass and resin over it all

you can make boats from the stuff so it must be waterproof