How best to cover/smooth this floor (with a manhole cover in the middle of it)

ijrwe

My bathroom floor is level but pitted and damaged, and much of it is covered with tile adhesive:



There is also a manhole cover in the middle of the floor:



The rim is below floor level (by a few mm) so doesn't stand proud of the surface at all.

It seems easiest to me to just screw 9mm ply onto the whole floor, having a separate sheet that just covers the manhole (and a few inches around) that could be removed if ever required. On top of all this I'm planning on putting down vinyl tiles which could be cheaply replaced, where needed, if I ever had to lift the floor.

I'm told already that "you can't do that", with regard to the ply, but I'm not sure why. I can't think of a realistic way to use self-levelling compound due to the manhole cover. I'd have to build a dam around it, pour the compound on the rest of the floor, then remove the dam and build up some material (ply, I suppose) in and around the hatch to match the new floor height exactly, and I don't think I could achieve that.


Any opinions?

Thanks,

themull1

Why is there a manhole cover in the middle of your floor?

Steffi747

Is that a sink pedestal standing over part of the manhole cover? :eek:

If I had this same issue I'd do as you described; dam the manhole and pour SLC.

If you are going to use vinyl tiles you can just clean up the rim of the manhole cover, build up with ply to your required height so its flush with the floor and tile the cover and make good.

Btw, I am by no means a professional, it's just what I would do from a DIY POV.

ijrwe

Steffi747 wrote: »

If you are going to use vinyl tiles you can just clean up the rim of the manhole cover, build up with ply to your required height so its flush with the floor and tile the cover and make good.

I'm concerned that I wouldn't be able to. Even a 1mm difference will make a noticeable line under the floor, how would I get the manhole cap (ply or whatever) to exactly match the floor height around it? I'm not sure I could achieve that.

bluetuesday_2

You could attach the ply to the manhole cover before using self levelling compound. Just keep on pouring until the SLC matches the ply height instead of matching the other way round

Alternatively there is nothing stopping you from plying the whole floor as long as it's marine ply or some such waterproof material. With vinyl tiles water can seep between the gaps and rot the floor. Sheet vinyl with ply would be the easiest and safest way in my opinion

Also not a builder, just a diyer

ijrwe

bluetuesday wrote: »

You could attach the ply to the manhole cover before using self levelling compound. Just keep on pouring until the SLC matches the ply height instead of matching the other way round

Alternatively there is nothing stopping you from plying the whole floor as long as it's marine ply or some such waterproof material. With vinyl tiles water can seep between the gaps and rot the floor. Sheet vinyl with ply would be the easiest and safest way in my opinion

Also not a builder, just a diyer

So like this, then, putting the ply lid in place first (sealing round the edges to stop the SLC flowing under?):



I would have to use very thin ply for that (SLC is only suitable for about 5mm?) but that's OK as it would be supported underneath by other padding in the recess of the manhole cover.

WRT fixing ply all over, I realised that also there are a number of copper water pipes set into the concrete at a shallow depth and I don't know where. I have a prediction of their route but I'm not sure at all. If I hit one with my drill I'd probably just sell the house, grab my tent and disappear forever.

Steffi747

Was the manhole cover also tiled?

I'd be looking outside to see if there is another manhole cover that may make the bathroom one redundant? That might give you more options.

Is this a job you definitely want to attempt yourself? Could you get a plumber around for advice? I'm sure they would have come across something similar before.

ijrwe

Steffi747 wrote: »

Was the manhole cover also tiled?

No, it was crudely padded up to tile level with scraps of wood, then the whole room was carpeted. I suspect that there were once tiles across it all but they had to get access and then afterwards just patched it up and hid it with carpet.

I'd be looking outside to see if there is another manhole cover that may make the bathroom one redundant? That might give you more options.

I'm end of terrace and my neighbour has one in the "same" location, theirs is outside though as they don't have this extension. I'm assured that blocking it is very irresponsible and, of course, if I did then I'd have some need to access it again in a few months...

Is this a job you definitely want to attempt yourself?

Zero income for a year now, on a pretty tight budget! The bathroom will cost over a grand even if I DIY everything, can't really be paying someone to do the floor as well. I'll give it a shot, I suppose I can't really mess it up too badly.

Could you get a plumber around for advice? I'm sure they would have come across something similar before.

I had a flooring guy laying some carpet in another room and he noticed it, said he's seen them before and basically told me the same - just keep it accessible without too much disruption.

Owain_Moneysaver

The frame of the manhole is supposed to be flush with the final floor level, so the cover can be infilled with matching floor finish.

best option would be to get builder to remove the manhole frame and re-bed it so it's at the correct level.

vaio

Yep, and move it out from under the sink pedestal whilst they are at it

Fitting & getting the levels right is fiddly but shouldn't be expensive.

Something like this