Cutting into 7" deep joists

[Cambridge Mum]

Hello, I have tried searching the archive and tried looking up stuff in the Building Regs, but with no luck. Please, does anyone know whether it is OK to cut into 7" deep joists (to run 2 22mm pipes across them) without reinforcing the floor? My installer yesterday did this. It looked as though he was taking enormous chunks out of the joists. Now in one corner, when I steppe on it to clear up this morning, the floor moved a bit, the pipes under the floor at the point rattled and the radiator about 15' away on the other side of the room made a noise. Is the floor dangerous?

I phone the local Council's Building Regs people and was told you can't cut into a 7" joist without reinforcing it. I have tried to check out this information but couldn't find anything. The Building Regs man said it would be a good idea to get an independent Structural Engineer out: before I do this I thought I'd speak to people here. Of course I shall get the engineer if it's necessary becasue I can't have the floor collapsing. The job was done by a Warm Front installer, by the way, so I had no choice of the firm.

 

[seco services]

22.5mm on a 7" joist.
and providing its in the right distance from the end.

sounds like the pipes just need a few clips and abit of hairfelt on the pipes over the joists

 

[kevplumb]

yup its not how its where and how much width / depth

 

[londonboy]

Thats how pipes are run in almost every single house in the uk!

The rattling can probably be sorted by fixing the floorboards back with screws

 

[seco services]

i don't think theirs a house around that has followed that reg to detail.
take the average house built in the 60's has had a number of different plumbers, diyers and then look under the floorboards.

 

[electronicsuk]

There's joists in my parents house that have had almost 1/3 of their depth removed by the idiot that owned the house prior to them, and the floors haven't caved in yet. There doesn't seem to be too much cause for concern, but this article covers what you should and shouldn't do when notching or drilling joists.

 

[cider]

is it not 20% cut out but no cut out if 100mm or less

 

[Cambridge Mum]

Thank you everyone for your replies - and for the link to that paper. Looks as though the Building Regs man may have been wrong.

 

[seco services]

Looks as though the Building Regs man may have been wrong.

not the first time.

 

[big-all]

is it not 20% cut out but no cut out if 100mm or less

its 1/8th or 12.5% notched or 1/4 25% hole wuth other restrictions

 

[clf-gas]

Seriously

I mean

 

[muggles]

Yup big-all is correct, and you may only notch in the area between 7% and 25% of the unsupported span of the joist

 

[namsag]

Yet to see a heating system that has been fitted to match distance and depth guielines, also thickness of joists come into it

 

[cider]

So I was correct, it is not 20%

 

[Cambridge Mum]

O dear, I just measure the joist and the cut out part. The joist is 17cm deep, the cut out 4 cm deep - so they've taken out nearly 25% of the depth. I shall definitely be asking them to reinforce the joists now.