40mm Waste across Joists.

[jackplumb]

This is a big no no, I know that but, are ther any methods for replacing the strength that has been removed by using plates or "Fish Plates" drilled and bolted through the joist.

 

[Mike Jackson]

Yes but you'll need calculations from a structural engineer. A couple of years back an engineer working for the same firm as me notched some joists for a gas pipe far too deep and they had to get a structural engineer in to calculate the plates required, cost the company a fortune.

 

[snowhead]

Are you notching or drilling?

 

[jackplumb]

Notching but I could drill and solvent weld lengths together.

 

[a12jpm]

Don't know if this helps but the IET say we (I'm a spark) can drill a joist no greater than 0.25 x the joist depth and at least 50mm from top or bottom of the joist. I assume someone somewhere has done some calculations to base this advise on, but as usual apply the @**e covering technique and get someone else to make the decision like a structural engineer. Remedial's on joists will never be cheap.

 

[Veggie Dave]

I went to a house last year to repair some DIY plumbing the home owner had done (nothing serious, his work was, as a whole, no worse than some of the 'professional' plumbing I've seen), when I noticed he'd 'notched' a joist to get the waste to the soil stack.

He'd notched 50% of the joist, around 350mm from the wall!

 

[SafeGasInstall]

did it once and end it up paying for 7 new joists and all the labour cost to woody and sparky

will never ever do it again

 

[Bernie2]

A mate of mine notched 2" deep into a 4" x 2" joist. I could hardly talk when I saw it.

 

[R1CKY]

I asked a "qualified" plumber to drill 4 holes to pass 22mm through. Stupid muppet drilled them vertically! Managed to stop him halfway through the second hole!!