Wall hung toilets again - sanity check on floor loading

[bblaukopf]

The wall hung wc is going to be mounted on a metal frame, with legs that go down to the ground. They are going to be resting on some 18mm chipboard fl ooring, about half way between two joists.

The live +dead load per leg could be 100kg, so far as I can see (frame, toi let, water, person sitting down on toilet, child on them). Dead load might be nearer 30kg.

I can't find any details on what sort of load chipboard might support, but it feels a bit high.

My idea is to route out a channel, 15mm deep, spanning two joists, and ins et a 50x15mm mild steel plate under each leg to carry the load. The legs th emselves need to be screwed to the floor, so I'll have them resting on a bl ock of wood which goes all the way back to the wall.

Will this work? Am I over-thinking this; should I just whack it in with no reinforcement?

L = leg W = wood S = steel (chipboard omitted from diagram) J = joist

L L L WWWWWW SSSSSSSSSSSSSS JJ JJ JJ JJ JJ JJ

[Phil]

go down to the ground. They are going to be resting on some 18mm chipboard flooring, about half way between two joists.

oilet, water, person sitting down on toilet, child on them). Dead load migh t be nearer 30kg.

t it feels a bit high.

nset a 50x15mm mild steel plate under each leg to carry the load. The legs themselves need to be screwed to the floor, so I'll have them resting on a block of wood which goes all the way back to the wall.

o reinforcement?

So, how much of this load is the wall going to take?

[bblaukopf]

e:

t go down to the ground. They are going to be resting on some 18mm chipboar d flooring, about half way between two joists.

toilet, water, person sitting down on toilet, child on them). Dead load mi ght be nearer 30kg.

but it feels a bit high.

inset a 50x15mm mild steel plate under each leg to carry the load. The leg s themselves need to be screwed to the floor, so I'll have them resting on a block of wood which goes all the way back to the wall.

no reinforcement?

Close to zero, I should think. The wall handles the moment, the floor handl es the load.

[bblaukopf]

Oh, I see what you're asking. The frame is mounted against the wall, not in it.

[newshound]

Makes some sense to me given that chipboard goes soggy if it gets damp. However I think I would be inclined to cut away the chipboard and use a single piece of timber or 18 mm plywood spanning the appropriate joists, and supporting the legs.

[dom]

Insetting a 15mm plate sounds overkill. The wall-hung WC frames I've installed had adjustable legs, so surface mounting a sheet-metal or timber plate should be possible.

[harryagain]

The live +dead load per leg could be 100kg, so far as I can see (frame, toilet, water, person sitting down on toilet, child on them). Dead load might be nearer 30kg.

I can't find any details on what sort of load chipboard might support, but it feels a bit high.

My idea is to route out a channel, 15mm deep, spanning two joists, and inset a 50x15mm mild steel plate under each leg to carry the load. The legs themselves need to be screwed to the floor, so I'll have them resting on a block of wood which goes all the way back to the wall.

Will this work? Am I over-thinking this; should I just whack it in with no reinforcement?

L = leg W = wood S = steel (chipboard omitted from diagram) J = joist

L L L WWWWWW SSSSSSSSSSSSSS JJ JJ JJ JJ JJ JJ

I agree centre of chipboard is not good I would cut away the chipboard and put in a substantial timber trimmer (ie at rt angles to the joists and secured to them with joist hangers). A bit of thick ply or timber on top tp replace floor boards.

Joist hangers

.

[bblaukopf]

Surface mount is not an option because it will protrude forward of the face of the frame, making a step in the FFL.

[bblaukopf]

For interest, I just found this:

which has quite a few useful figures (see p23).

Point load, humid conditions, 22mm P5 - max 2.6kN at 400mm centres. Max uniform dl - 11.3kN/m2

[bblaukopf]

I discounted that option initially (because there's a pipe in the way, imme diately beneath the chipboard). But I think I will go down that route - I'l l make a noggin with a large notch in the top, and then bond it to the repl acement flooring with enough screws to make it function like a single beam (which will make it much stronger in bending). The joist hangers will then be unnecessary anyway.

P = 18mm plywood floor. W = wood trimmer

PPPPPPPPPPPPPPP WWWW WWWW WWWW WWWW WWWWWWWWW WWWWWWWWW WWWWWWWWW

[dom]

The design must be different to the frames that I've used (Grohe). In one instance it was convenient to the stand the frame on the sole-plate of the stud wall in which the frame was incorporated.

[bblaukopf]

My joists run parallel to the frame face, not perpendicular to it - so I could add a sole plate, but it wouldn't help much.

[dom]

Well you know your project best. I'd have thought a 45mm thick stud/sole-plate would be a big help in spreading the load.

[Jim K]

So put some noggins between the joists (big nails/screws) so the new noggins are under the legs, then repair flooring surface not using chipboard in susceptible areas.

Jim K

[RobertL]

Would you worry about the loading of an ordinary loo on the floor at the same posiiton? is it the fact that the loading is onto a smaller area than a normal loo that causes the worry?

Robert