Hole in joist

Considering a low shower tray.

Currently the bath waste goes out through wall above floor level.

To have a low tray I would need a lower waste - this would mean cutting a hole through one joist - one next to the wall.

Is this permited?

Reply to
DerbyBorn
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I suppose it depends on the size of hole and depth of joist. The place to drill it is near its end no more than a 1/4 of the way along, it might also be useful to attach some metal straps around it. I should imagine there are some guidelines for making holes in joists just do,not know where you would find them. I should imagine you are not the first to have to route a water pipe across joists as opposed to parallel to them.

Richard

Reply to
Tricky Dicky

There are rules about which parts of the joist can be drilled or notched.

From memory holes must be in the centre line at between 25% to 33% of the joist length and the diameter has to be 25% or less than the joist depth.

Different rules apply to notches and also there are rules about minimum distances between notches and holes.

Think you will find this link useful

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These rules help to avoid structurally weakening the joist, and you will need to have a look to see what holes or notches already exist on the joist you want to drill.

Reply to
stephenten

You definitely can't have a step up into the shower?

Reply to
GB

GB snipped-for-privacy@microsoft.com wrote in news:q2pegm$abo$ snipped-for-privacy@dont-email.me:

I don't want to - getting rid of bath due to wife's mobility issues. Want to be "future proof".

Reply to
DerbyBorn

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Going from the link provided above you should easily be able to drill a hole for a standard 11/2" waste pipe in an 8" joist.

Richard

Reply to
Tricky Dicky

Useful link. In reality, for the joist nearest the wall, especially if the hole is near to the end, there will be quite a lot of conservatism in the calculations and I would expect a "two inch" hole in a "five inch" joist to be fine. If it is near the bottom, i.e. in the "tension" side then you could always screw some metal strip across the weakend area, either on vertical faces or the bottom one if that is accessible.

But I am pretty sure that I wouldn't bother. Try not to get caught, obviously.

Reply to
newshound

Provided it's in the central line and within 25 to 40% of the span and a minimum of 3 X the diameter from any other hole or notch.

In reality the hole will need to be slightly larger than the pipe diameter to allow for the pipe fall and for expansion/movement of pipe due to hot water going through it and also for expansion and shrinkage of joist due to ambient temperature and humidity

Reply to
stephenten

Interesting. One of ours has been badly chewed by a squirrel that I ignored for too long. I shall try to somehow check it against that.

Reply to
Dan S. MacAbre

Have you considered a shower waste pump? A bit expensive, though:

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Reply to
Jeff Layman

He needs that like he needs a hole in the joist.

NT

Reply to
tabbypurr

The guideline for holes are that it should be no more that 1/4 of the joist depth in diameter, and they must be on the centre line, at least

25% of the length from the ends of the joist.

If notching, then you must be between 0.07 and 0.25 x the span from the end, and no more than 1/8th of the depth.

So for a 4m 200mm deep joist, you can have a hole up to 50mm diameter, and it must be at least 1m from the ends. If you need an additional hole, then it should be at least 3 diameters away from any adjacent hole.

You can have a notch of up to 25mm depth, but it must be between 280mm and 1m from either end.

(in reality you can get away with a bit more if you use common sense and think about what loadings there are in the actual location)

Reply to
John Rumm

As the OP says that it is next to the wall, I wonder how close? Our closest is less than 3" from the wall. If I wanted to put a largish hole through it, I'd put a piece of timber between the joist and the wall on either side of the hole and rawlbolt the joist to the wall for support.

Chances are anyway that the joists were sized for a full bath and a shower tray will put much less load on them, so a hole will be pretty unimportant.

SteveW

Reply to
Steve Walker

It is an alternative that nobody else has mentioned, and just in case he can't use a hole in the joist. I happen to use one to pump water from a garage sink lower than the house to the house waste pipes. It's very reliable and works well.

If he can't have a hole in the joist or use the saniflo pump, what are you suggesting he actually does do?

Reply to
Jeff Layman

No direct load on this joist as it is right next to the wall - the next joist in takes the bath weight

Reply to
DerbyBorn

Can you fit a plate to it in some way, then it should not matter if its fixed well. Brian

Reply to
Brian Gaff

a) Zero cost & perfect reliability or b) expensive, bound to fail, more likely to block & requires an electrical supply

where do you get that one from?

Come on, there's no mystery here. This is trivial.

NT

Reply to
tabbypurr

I thought that you were going to say that.

Obviously, the hole in the joist is just part of it. Scaffold tower. Hole in the wall. Hole in the down pipe and coupling. Etc.

I was just checking you really needed all that. :)

Reply to
GB

it shouldn't be a problem but, in any case, there may be alternatives.

What is under the joist - presumably a ceiling above another room? Is there any scope for going down and our through the wall *under* the joist - making a 'feature' of whatever boxing you put round it in the room below?

We effectively did that then we concerted a garage to a kitchen. The waste pipes from the shower and washbasin in the en-suite above went out below the garage ceiling joists. In the kitchen conversion, we put a step in the ceiling about 6" from the end and but a piece of wood trim right across, extending slightly below the step - with a strip-light hidden behind it.

Reply to
Roger Mills

I was coming to the same views - especially with the foul stack.

Will re-calibrate wife towards a raised shower tray (pity though)

Reply to
DerbyBorn

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