Say you had a plank supported on bricks either end. Do you think sprayfoam under the middle would stop it flexing? The clear answer is no - put a brick(s) under the middle too.
That's like saying a sponge is as solid as concrete just because it fills the space? You will never convince me the sprayfoam is as ungiving as concrete... because it plainly is not! Maybe you think I'm just trying to fill a void?
Spray foam does go hard and doesn’t compress under normal circumstances. I certainly wouldn’t want to wash the car with the “foam”.
For sure - hard, but... Have you stood on a chunk? Hint: I have. I'll be using concrete, if this tray cracks I'd have to rip out the entire cubicle and start again - why risk it?
I’ve sawn some after fitting windows … surprisingly strong stuff… bit of flex, but thought that would be a good thing on a boat. Used it to strengthen lads “bargain “ shower cubicle…. still good a year on.
Advising Zed is pretty pointless mostly as he knows what he’s going to do before he does it he just likes to draw out comments!
It's a steel boat, I hope it doesn't flex too much. Corners and middle of the tray are on concrete so your "bit of flex" to my mind makes squirting foam under the rest of it pointless. I'm not in the mood to experiment, I've been hacking away at this boat for almost 4 months now and if I had to do a chunk of it again I think I'd have a nervous breakdown*. *It's really very hard working in a narrowboat compared to a house - nowhere to put anything, nowhere to work. It's like trying to make a 6x8 shed inside a 6x8 shed surrounded by water with a door that's too small to get the materials through. lol
I'm just politely answering rather than ignoring the suggestions actually. I didn't ask for advice this time, I just mentioned I'm not happy with my tray installation and I'm going to shove some more concrete under to remedy what I see as it's shortcomings.
Shouldn’t have liked this really….I feel your pain…. and I’ve only got a better half who doesn’t like anything in house…even when it’s the stuff I’m using to do a job she’s requested. Bus is in the air whilst I sort the engine…the inside is now full of about 20m2 of wooden flooring.
We used to fill the voids in fibreglass arches and side skirts with spray foam then trim it just below level and seal it over with a few layers of fibreglass. It’s quite impressive how much stronger it made them. Not telling you to use spray foam Steve Just musing and remembering how surprised I was at the added strength it gave.
Dry-ish mix, no hurry for it to set so that will help? It's a bit off a crap shoot tbh, I had to get a tray with the drain in one particular corner and low enough to fit a standard door on top. This was the only one I could find on the web that fit the spec and sadly it was el cheapo crappo lightweight badly made rubbish. Funny really - usually the only option for stuff once you narrow down your needs is the most expensive one!
I've used it once in a while, first time was when it was a new novelty back in the early eighties. Naturally it would have been perfect as you used it, a bit of a miracle solution. But I've never seen compressive strength highlighted as a selling feature - flexibility maybe, and gap filling without doubt. Horses for courses.
I once had the dubious pleasure of fitting a boiler in a house in Spain that was a concrete frame with foam blocks. I presume the concrete was to stop the foam compressing. Annoyingly the house was rendered and the owner forgot to tell me it wasn’t an ordinary ladrillo and render construction beforehand . Drilling into concrete with metal bats in, or trying to hang a boiler on foam blocks isn’t funny!
Could have and did, there is 36mm of construction ply then the concrete as well as doubling up the supports under the ply. No point having concrete on top of a bendy base. You do realise that this shower is 99% finished? But there is a gap where I could and intend to shove more concrete in. I didn't think it through properly and to avoid slipping, one is always going to put one's foot just inside the door, just where my concrete is lacking. If I don't do it, I'll kick myself if it cracks and this seems to be just where they do crack. If I do pack it and it cracks anyway, at least I'll know it's not because I couldn't be bothered to stuff some concrete in there. You know how it is - you have an idea like this, you have to follow through if only to stop thinking about it.