Deep notch in floor beam for shower trap.

frank999 · 11 Feb 2020

I wish to put in a shower tray in a loft extension - the trap fouls a 3.3mt 220mm beam directly below it.

Going by Reg's, I can put a 27.5mm notch on the beam, at max 850mm from beam end.

I need to make an approx 60mm notch at 1mt, even then the 60mm does not allow me to unscrew the base of the trap.

Bit foxed about how to resolve this, bathroom stud walls are all in - plastered other side.

Could you double a rafter with such a notch, or trim out the section.

A riser kit makes the shower panel a very tight fit against the pitched roof, but guess thats an option, if it will fit.

^woody^ · 11 Feb 2020

Yeah. Nail some 600mm x 11mm ply either side though

John D v2.0 · 11 Feb 2020

I assume not, but can you turn the tray 180 degrees?
I put our outlet at the door end of the tray, and used a flush grid drain to help with clearance issues so it may work for you too.

Also no need to use the standard riser kit, we only needed about 60mm as well so I just put 2 inch battens and a sheet of 18mm ply to get the height I needed. I think the riser kit would have added double that.

plastic_peanut · 11 Feb 2020

Could do with more pictures really. Initial thoughts are to look at a tray with a linear waste. If not could you build the wall out to step the waste into the cavity beyond the joist?

frank999 · 12 Feb 2020

Thanks for the replies, I can make a 50mm rise which would help, and if I go notch out 80mm I can then remove the base of the trap if I ever needed to - such as a bad blockage.

"Yeah. Nail some 600mm x 11mm ply either side though" - is that either size of the notched beam your refer to ? ... how about notching out the 80mm, then bolting a 6x2 to the existing 9x2 ... how many bolts/what length of 6x2 each side of the notch would suffice, one end would bear into the webbing of the steel, 2 bolts either side of notch?

I can't turn the tray, its all very tight in the loft bathroom - the shower has a sink to the left, the curve of the door in the position its in allows reasonabe access to the sink.

"linear waste". will take a look, thanks.
If not could you build the wall out to step the waste into the cavity beyond the joist? - it then fouls the door.
Will post up some more pics.

Nige F · 12 Feb 2020

frank999 said:
Thanks for the replies, I can make a 50mm rise which would help, and if I go notch out 80mm I can then remove the base of the trap if I ever needed to - such as a bad blockage.
.

A lot of shower traps come apart from above for cleaning

frank999 · 12 Feb 2020

Thanks - that would reduce the notch depth required ... with a 50mm riser - it might even be within Regs, give or take the 150mm span difference.

Guess I could remove the 22mm T&G flooring if its tight under the ceiling, but have another concern around noise to the room below if I do that, will pack out with insulation underneath and foam all gaps.

frank999 · 25 Feb 2020

This did my nut in, ended up raising tray up 50mm, and routing waste over steel, has a fall - of sorts. Floor will also be part raised in the bathroom by 22 mm (thickness of T&G flooring).

Next time I plan it better, trapped (excuse the pun) by two large steels, very difficult, not sure how you could plan it better - apart from moving bathroom well away from its current position.

Thought about routing it down through a toilet stud wall below - although beleive a vertical drop would suck anything out of your trap.

23vc · 25 Feb 2020

Did you bend the basin waste over your knee? Careful when screwing the flooring down

John D v2.0 · 25 Feb 2020

frank999 said:
Thought about routing it down through a toilet stud wall below - although beleive a vertical drop would suck anything out of your trap.

Vertical drop would only do that without an aav. You need an aav or a vent at the top of any significant drop and you would need to do 50mm pipe really. Although a normal shower wouldn't fill the pipe in the same way as emptying a bath or basin would.
We had a similar issue when we moved in, 40mm pipe going uphill, and we managed to fit a 50mm pipe (55 o/d) inside a stud wall with 70mm studs somehow.
The stak terminates at the bottom just under the ground floor into a 110mm pipe combined with a toilet and at the top in the loft with an aav.

frank999 · 8 Mar 2020

Did you bend the basin waste over your knee?
Used a hot air gun, gently ! then applied a bit if pressure, too much heat and the pipe turns to mush.

Careful when screwing the flooring down
Yes the bloke with the impact driver has a habit of screwing through things, previously a 15mm water copper pipe, and 1.5 T&E lighting circuit, a lot of work to put right. I've been putting in a lot of drill plates this time round.

frank999 · 8 Mar 2020

Presume air admitance valves should be installed on a branch at a certain height above the point of entry or above height of sink/bath etc?

Hugh Jaleak · 12 Mar 2020

Use an anti vac trap on the basin. Where does the soil go to?

James45632 · 12 Mar 2020

Cut away a portion of the joist that's in the way, then double the joists on the left and right. Add horizontal 'trimmers' between the doubled joists.

There's a picture of it here:

https://www.diynot.com/diy/threads/doubling-up-rafters-for-velux.397972/

The idea is the same as if you were creating an opening for a velux window.

frank999 · 10 Apr 2020

Use an anti vac trap on the basin. Where does the soil go to?

Do I T off just before the U Bend on the sink out let, does the AAV need to branch out sideways and up, and be situiated higher than the sink plug ...

Cut away a portion of the joist that's in the way, then double the joists on the left and right

Agree, a good solution ... and to install before purlin walls, stud walls that sit no the joists, restraint straps, an array of electrical, network, alarm cabling and plumbed pipes that are fixed etc etc, ... the bathroom design all needs to be thought out before - trimmers can be retrofitted, but is twice the work ...

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Deep notch in floor beam for shower trap.

frank999

^woody^

John D v2.0

plastic_peanut

frank999

Nige F

frank999

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