Cutting into ceiling joist

[toxictoad]

Hey,

I'm fitting a new bath and in order to get it to the correct height, the joist under the waste pipe needs to be cut into.

The joist that needs to be cut into, spans a distance of 3.14 meters, is 18 cm deep, 5 cm wide and approx 37 cm apart from the joists than run parallel to it.

The cut needs to be the full width of the joist, starting 27 cm from the wall, 9 cm long and 8 cm deep.

The question is, would it be safe to do the cut without supporting the beam? Presuming it can be supported after reading this http://www.diydoctor.org.uk/projects/weakbeam.htm

Thanks

 

[freddiemercurystwin]

Sounds crazy to me http://www.eastdevon.gov.uk/bc-guidancenote7-notchingofjoists.pdf

 

[noseall]

Basically you are removing a joist (for what's left of it) right beneath a fully loaded bath. Not ideal. Time for a re-think.

We have had to create false panelling or boxing-in in the room below in order to accommodate shower and bath wastes in the room above.

 

[toxictoad]

Yeah, had a re-think.

I can move the bath to the right 6 cm and put a panel in to cover the gap between the head of the bath and the wall. This will mean I just remove 9 cm x 5 cm off the floorboards and avoid the joist completely. The hole will be hidden by the bath panel.

That works for me.

 

[footprints]

Can you not get away with a shallow bath trap?

http://www.screwfix.com/p/shallow-bath-trap-40mm/13034

Depends on the discharge of the waste though.

 

[ree]

OP,
google - header joist pics and hearth trimming joists pics.
Essentially, you could cut the troublesome joist all the way thro, or partially cut thro, and install a "header" to support the remaining length. Use 50mm joist hangers.

 

[toxictoad]

Thanks, the shallow bath trap might be an option but the bath is on the first floor and I don't know what a gully is and if I connect to one? (probably not I guess)

"Suitable for use in most ground floor situations where the discharge waste pipe is going direct to a gully"

Image search for header joist - http://bit.ly/1z3pYkk
Don't really know what I'm looking for and there's lots of different things. To be honest, this looks a lot more complicated than moving the bath and putting a panel in to cover the gap.

 

[ree]

Are you serious? You would rather move a bath with all that implies in terms of moving the plumbing and re-arranging the other fixtures and tiling - rather than study a simple diagram for five minutes and chop off a bit of joist?

 

[freddiemercurystwin]

Are you serious? You would rather move a bath with all that implies in terms of moving the plumbing and re-arranging the other fixtures and tiling - rather than study a simple diagram for five minutes and chop off a bit of joist?

And don't forget the OSB under the tiles either?

 

[theprinceofdarkness]

In you first post you said that the notch was 9cm long and 8 cms deep. This is nonsense there is no law which says that the trap has to be in line with the bath, turn it sideways, use a 32 mm pipe and turn the pipe parallel to the axis of the bath in between the joists and under the floorboards. The biggest notch you ever need to use is for the width of the pipe.
Most baths are configured to accept a trap above the floor (concrete floors in flats or bungalows) do a bit more research.
Frank

 

[footprints]

As I understand it (and I will certainly be put right if not! ) low traps are OK for discharging directly into a gully (open grating in the garden) or a hopper head on the outside wall. The problem comes when they are connected into other pipes like a 4" stack pipe as the shallow trap can be siphoned out when other pipes are in use.

 

[theprinceofdarkness]

This is a theoretical proposition, as most stack pipes are vented it is not likely to happen. FWIW my present bath has a shallow trap into a vented stack along with a toilet and hand basin, the trap has not been sucked out yet in 12 years. Its also a holiday cottage, so there is a chance that the water in the trap could evaporate between visits.
Frank

 

[HawkEye244]

I had a problem in my first floor bathroom because the shower is at the other end of the room, so would require a 40mm dia hold through at least 3 adjacent joists to reach the internal stack. I decided to run the pipes along the perimeter and then box in using treated battens and some 12mm ply, looks reasonably good, saved loads of time and good peace of mind. I had to raise the shower up about 200mm to get enough fall so fitted a little step up to it which was then tiled

 

[HawkEye244]

OP,
google - header joist pics and hearth trimming joists pics.
Essentially, you could cut the troublesome joist all the way thro, or partially cut thro, and install a "header" to support the remaining length. Use 50mm joist hangers.

Interesting although that splits the load between two joists rather than three, so with a bath full of water and a big hippo in there aren't you asking for problems?

 

[ree]

No way - the only piece of missing joist is well within safe limits near the end of the span.
If the trimming or heading off came in the centre of the span then all boxing in timbers would be doubled.

This is how timber framed house floors are framed from new.