4" hole on 8" x 2" floor joist

[Nige F]

Spot on Freddie - and a good link Also possibly easier for a "competent DIY`er" to do the metalwork - @ a real push it could be done with a hacksaw inserted through a small elongated hole ,take the blade out the frame - pass through the hole and replace frame - Pillar drill would be nice for the holes . I used to do a bit of metal bashing , making brackets etc for a trike I used to have . Lifted up a drain gulley that was outside my garage ( one of those heavy iron roadside ones hinged @ the back) and used it as an anvil

 

[markspark101]

Got it! Thanks everyone. I'll give it a go.....

 

[nick31]

Get 2 bits of 3mm thick steel plate, around 600m long by 200mm high, with a (slightly larger than) 4" hole plasma cut in the middle.
Reinforce the joist by bolting either side with ,say, 4 M10s either side of the hole (150mm centres lengthways, 120mm centres on height.

Yeah that's what I would do too.