Drilling Flat Roof Joists

[Gravid]

Are we allowed to do this ? If yes is it the same hole size/distances as floor joists ?

I normally use the safe zones, but this isn't possible as its like an all glass byfold door type extension.

I'm thinking I can as surely floor joists have just as much weight on them, thought I'd see what you lot think.

Thanks for any replies.

 

[Spudnik]

I would and have treated flat roof joists the same as floor joists.

 

[flukey]

i was taught never to drill roof joists. they are a lot smaller than floor joists

just looked in on site guide and it seems that it is perfectly acceptable

 

[Des 56]

Only once asked an archetects permission to do so and was turned down flat(get the pun)
It probably compromises the structural integrity,so unless its huge then why not use the wall safe zone and the joist available direction

 

[Spudnik]

I think you chaps maybe getting confused between rafters (which hold the tiles) and joists of a flat roof.

Flat roof joists are normally the same size as a standard floor joist so drilling within the correct zones is ok.

Rafters, are normally 4", however, i have seen more and more 6" going in, which should still NOT be drilled.

Only once asked an archetects permission to do so and was turned down flat(get the pun)
It probably compromises the structural integrity,so unless its huge then why not use the wall safe zone and the joist available direction

Interesting point there Des, as i have drilled them and never been questioned by LABC.

 

[flukey]

didnt read the FLAT part in the op

age 59 osg appears to allow you to drill joists above any ceiling

got me thinking now

 

[Des 56]

When I asked for permission the roof was going to support a new room above a bugalow which had a part flat roof
Perhaps it makes a difference if it supports only the roof

I used one hell of a lot of cable for what could have been a lot less(in and out of the joists)
Admittedly if he were not involved I would have perhaps used a different method of installing the cables

 

[Gravid]

Only once asked an archetects permission to do so and was turned down flat(get the pun)
It probably compromises the structural integrity,so unless its huge then why not use the wall safe zone and the joist available direction

There's no available zone, on two sides it's glass and there's RSJ's on all 4 sides, the two brick sides have RSJ's one with joists resting in it supporting the flat roof with no space behind them. Even getting my switch wire/neutrals up is going to tricky.

I've never seen anything built so damn well. There's normally always a way but couldn't see one today.

They are the same size as the floor joists.

Your right flukey, never noticed that it does say ceiling support.

 

[Spudnik]

I think your best course of action is to speak to your scheme provider or LABC officer.

Let us know the result.

 

[Gravid]

Ok no probs. Thanks all.

After 4 attempts at getting hold of building control and being put through to the planning department i gave up on

them, the governing body said its fine to drill them aslong as you stick to the same rules as joists, .25 of depth for hole

size and between .4 and .25 of span.

 

[sparks1234]

i was taught never to drill roof joists. they are a lot smaller than floor joists

just looked in on site guide and it seems that it is perfectly acceptable

Generally flat roof joists would be larger than a pitch roof

 

[High Tower]

Get the drill out, and if anyone says anything then repeat after me : Me no speakie englishio

 

[flukey]

Generally flat roof joists would be larger than a pitch roof

keep up, there was another post after this one