Notching Ground Floor Joists

[j0nb0y]

I have a plumber fitting a brand new heating system in my house, He has notched the ground floor 4" x 2" ( 47 x 100mm) joists to accommodate the flow and return pipes 22mm. Is this acceptable building practice? Or will this not weaken my living room floor considerably?

Also does anyone know the minimum distance between the flue and any opening window, I was under the impression it is a minimum of 300mm (12")

Any advice before I tackle my plumber would be much appreciated.

[Clanad]

I'm sure The Builder willbe along to answer your question aptly... However, being as I am in the U.S. I guess I'm astounded that floor joists in the U.K. can be 2 X 4 (which is the terminology used here). The minimum floor joist here, depending on span) is 4" X 8" and more likely 4" X 10" if the apan exceeds 14 feet. Of course, most modern houses (built in the last 10 years, say) use floor trusses built from your 4" X 2", but to my knowledge, those absolutely cannot be notched or otherwise cut, since it would destroy the structural integrity.

If in fac,t your floor joists are stand alone 4" X 2", I'd find it unacceptable to cut into the joist by almost 1/4 of the width (seeing as they aren't truly 4" wide anyway). But check with your local building codes if some of the more astute (with UK laws) craftsmen don't come along...

[The Builder]

Here's a simple checksheet, Jonboy.
It's for electricians, but the same applies.............

http://niceic.com/Uploads/File3777.pdf

Yes, 300mm horizontally for flue to opening window. I'll check it out and get back to you.

[Clanad]

Aha... should have pre-read my post... I wrote "...is 4" X 8" and more likely 4" X 10" if the span exceeds 14 feet..." but what I meant was 2"X8" and more likely 2"X10"... etc...

[The Builder]

To answer Clanad's point............ I agree, 2 x 4 is not a great size for notching. Spans are taken from tables of values. 2 x 4 in free span would be a very narrow room.

In Jonboy's case, it's a ground floor room I guess, with a suspended floor. If so, the joists are picked up at fairly close intervals by "dwarf walls". This reduces the span so as to make greater sized joists unnecessary.

If I've assumed correctly, I think I would choose to "sling" the pipework under the joists rather than notch.

If the notching is in the right places, it's Ok in this case, but not ideal.

[The Builder]

Here's a part of the Regs for flue siting, Jonboy.

Note that it's 600mm for oil boilers...........

http://www.nhbc.co.uk/Builders/Technicaladviceandsupport/TechnicalGuidance/68/filedownload,37239,en.pdf

[j0nb0y]

thanks for all the answers. Think the dwarf walls mean the span is only aprox. 2.1 m. He has notched them about 150mm from the ends near the party wall. Definitely not happy. Checked the boiler fitting instructions and it should be 300mm from window opening. he has positioned it less than 200mm

[alavahalf]

My guess would be to extend the flue away from the window using one of the many kits available for most boilers. At some point in the future when you have your boiler serviced this problem may be spotted and the boiler would be turned off by the service engineer.

Tell your 'plumber' about your concerns now.... He knows that if he installs a flue that doesn't meet today's regulations that he may well loose his Gas Safe certification.
But if he insists that it will be OK..... tell him you are going to ask for a second opinion from the Gas Safe Register ... he will extend it!

[malagabob]

In new build houses that use 4X2 joists, notching of joists are strictly controlled.
ie they must be within a certain distance from a supporting wall, not straight down the middle of the room.And each notch must be for each pipe individually not one large notch to carry both pipes.
Also your plumber must wrap hessian around each pipe to stop the noise of creaking caused by expansion.