Pipes under floorboards.

[Bazm]

Hi,
As you may see from my previous posts I am working on my bathroom,
which has turned into a bit of a nightmare.
The current problem was a dreaded plinth built by the previous owner,
in poor fashion in my opinion.
Now the plinth has gone and I am back to the normal floorboards
all pipes are now exposed. I have no option but to run them under
the floorboards.
The joists are 7 inches by 2 inches and 12 inches apart.
Ideally I would like to just lift one floorboard near the wall
and cut a notch in the top about 3 inches from the wall to accommodate
hot and cold water pipes about 7/8 inches deep.
I have looked at a few websites, and they seem to give conflicting
information.
Do you think I will be OK to go ahead with my plan, otherwise the
layout as it is means I will have to start taking down partition walls.

Thanks,
Baz.

 

[JPC]

http://www.zurich.co.uk/NR/rdonlyre...-0C6B2CD53EED/0/NotchingDrilling107780A02.pdf

above tells you your notching distances and depths.

in reality i dont know a plumber that just doesn't put a notch were he needs it (for 22 mm pipe max depth), wherever that might be

 

[doitall]

Notches should be no more than 12.5% of its depth and no further than 25% of the span from the end support.

Saying that a bath full of water could be a tonne in weight.

 

[ChrisR]

You shouldn't notch within (I thnk it's) 7% of the end either, DIA.

 

[chrishutt]

a bath full of water could be a tonne in weight.

Hard to imagine how you could go much above 300 kg, even with a cast iron bath. A typical bath full to overflow level will hold around 200 litres of water (200 kg) plus cast iron bath (100 kg?) plus fat person standing in it (no displacement of water - say 20 kg).

 

[doitall]

a bath full of water could be a tonne in weight.

Hard to imagine how you could go much above 300 kg, even with a cast iron bath. A typical bath full to overflow level will hold around 200 litres of water (200 kg) plus cast iron bath (100 kg?) plus fat person standing in it (no displacement of water - say 20 kg).

It was a terminology Chris. " weigh a ton" or at least 1/2 a ton in your example.

Still a lot on a 7" joist, and even worse when the op starts to butcher them down to 5 and a bit inches

 

[chrishutt]

But you said tonne (1000 kg), not ton, which sounds more technical than colloquial, like it's meant to be accurate. Anyway I was way out on my figure for fat person (I was thinking of stones, I guess) - 100 kg would be more like it, making 400 kg in total, getting on for 500 kg I suppose. I'm just being very nit picking this morning.

 

[WelshMan]

I beleive to work out the correct depth and notching distances is something like this.

Depth of notch is Height of joist/8 i.e 200m/8 = 25mm depth

Minimum Distance from wall is 0.07x span (length of joist)/ 100 = 7x2500mm/100 = 175mm

Maximum from wall is span/4= 2500/4 =625mm.

So basically you have a very narrow avenue of notching in a joist to comply with Building regs.