Joist notches

[radpotato]

Hi,
First post here; the builder I hired to fit my new bathroom (who I hired based on previous good experience) has gone OTT on joists supporting the 1st floor bathroom. He's notched out around 1/2 depth of four beams, three right close to the external load bearing wall and one around 20% along the beam length. This was to fit a waste pipe (he didn't ask me first - I would have thought the waste would go out and around the wall, or maybe boxed in above the floor). I've contacted building control at my local council, but I'm not sure what I should do next... Any suggestions for mitigation work (I assume the builder will need to do this)?
Cheers,
M

 

[radpotato]

Figured I should add some pictures...

 

[endecotp]

First make the notch even deeper (!!!) to give yourself a few mm to play with, then rebate the top of the joist either side of the notch slightly, and fit a metal plate across.

I think there are specific metal plates for this, but a quick google doesn't immediately find them. Someone else will probably be along in a minute with more experience than me.

 

[theprinceofdarkness]

If he is using the total depth of the slot, then the best way would be to sister pieces of metal to the sides of the butchered joists. If he is only using the bottom of the slots and you have a clear area on the top of the slot, then a piece of wood that is a tight fit glued in would would do the trick. The reason for this is that when a joist is loaded by a weight on it, the joist wants to curve, so the top of it is trying to push together while the bottom is trying to tear itself apart. The centre section does not change shape (much) so as the wood is not under load, it can be dispensed with.
You have not told us any dimensions, so Its guess work on my part, but once the pipes are installed, the joists need to be lifted up by a tiny amount, then a piece of 2" X 2" cut to be a tight fit in the now opened out slots, with its grain aligned with the joists. Slathered it with glue and tapped it into the slot. If it sits a bit high, it can be trimmed when the glue has gone off after a day. Once the piece is fitted, take the ceiling props down. The joists will now drop to their ordinary sitting point.
Frank

 

[^woody^]

Glue and screw 12mm ply, both sides and 1200mm long

 

[endecotp]

Actually your difficulty is that it's right up against the wall, so anything that needs to span the notch will be hard to anchor on the wall side. Hmmm.

(What are the dimensions of the joist? LxWxH)

 

[radpotato]

The joists are 6x2, the notches are all 2.5" - 3" deep. I'm wondering whether it's better to remove all the pipe, get the builder to send it out through the external wall? The notches at the ends of one of the joists is cut all the way to the end (as in, not a U cut), so no brace is possible over the top not an insert for that one. As they're in a series along the ceiling I'm assuming sistering them might not help all that much. Given there's no ceiling below (getting it re-plastered) and no permanent flooring above would it be better to demand the joists be replaced, or is that going over the top?

 

[endecotp]

Length?

 

[theprinceofdarkness]

Aaah!, the pics. The middle one is easy, just nail and glue on extra wood, predrilled with his holes, make them 2' long. The first one, you need to reinforce the bearing area on the wall. I would use two bits of angle iron, with one face on the wall top and the vertical section through bolted to the joist. The third one is very nasty, as explained the bottom of the joist is trying to tear iself apart, so a couple of steel strips which you can sneak under his hole and through bolted would hold it OK. As said before a piece of steel (4mm thick?) rebated into the underneath of the joist would fix it but it must be held in with three 3" X 5mm screws each side of the hole at 6" centres. This piece of steel could make plaster boarding tricky.
Frank

 

[radpotato]

The room is approx 8'6" wide.

 

[endecotp]

And the other number I should have asked for is joist spacing...

 

[roboughton]

I know you came for help but this builder obviously doesn't know what he's doing please get him off your site!!

 

[radpotato]

Spaced between a foot and 14" apart.

 

[endecotp]

They seem to be the right size, i.e. not massively over-engineered. So yes you do need to fix this!

 

[radpotato]

Building control at the council just got back to me echoing what's been said here. Can anyone advise how difficult (and rough price) it would be for a full replacement of four the joists?