Splicing a joist

entersandlady

I recently bought a house which I am in the process of doing up.

This week I had a company come in and do a half-a$$ed job of putting up an attic stairs. I have a list of complaints but my main one is the following:

In order to put up the stairs they had to cut a joist (which I understand) to fit the stairs. They spliced the joist, however my brother said the splice was no where near adequately long enough (about 1 foot either side of the attic stairs).

Can anyone (architect / engineer) tell me how long the splice should be on a rafter supporting joist??

mikeycoz

Did they put in extra struts? Anywhere they have joists joining, there needs to be a metal shoe. They should have doubled up the joist from both wall plates really. Why did they need to splice it? Usually I go about 3' on each length and have it cut in a key shape. Is it a truss roof or a cut roof?

DublinDilbert

Yea the joist was probably 580mm apart and they needed 610mm to fit in the stairs + shim. So they ran a joist along side the old one, bolted it on and cut the old one. This would give you 600mm for the stairs.

The bottom of truss is the chord member, this is normally in tension near the middle, but can have other forces on it too.

I would probably of went at least 60cm - 80cm either side and bolted & screwed the new / old together. But I usually over engineer!

chris445

Wha exactly do you mean they "spliced" the joist?

Splicing is a joint normally used to add extra length to a ridge board in a roof. Its basically just a diagonal joining that can sometime have a "key" at the top and bottom. I can't envision why they would splice a joist because it needed to be cut out of the way.

In any case a few pics would help if possible.

mikeycoz

DublinDilbert wrote: »

Yea the joist was probably 580mm apart and they needed 610mm to fit in the stairs + shim. So they ran a joist along side the old one, bolted it on and cut the old one. This would give you 600mm for the stairs.

The bottom of truss is the chord member, this is normally in tension near the middle, but can have other forces on it too.

I would probably of went at least 60cm - 80cm either side and bolted & screwed the new / old together. But I usually over engineer!

I have never seen anybody doing this. Is the trimmer and stairs to be held up with a few screws and bolts? 600 stairs?

cork2

entersandlady wrote: »

I recently bought a house which I am in the process of doing up.

This week I had a company come in and do a half-a$$ed job of putting up an attic stairs. I have a list of complaints but my main one is the following:

In order to put up the stairs they had to cut a joist (which I understand) to fit the stairs. They spliced the joist, however my brother said the splice was no where near adequately long enough (about 1 foot either side of the attic stairs).

Can anyone (architect / engineer) tell me how long the splice should be on a rafter supporting joist??

It's their mess make sure they fix it! Generally you shouldn't slice anything in this scenario. You cut out the ceiling joist to the required length, for arguments sake it'd be roughly 1200mm and you fit a trimmer on either end. The trimmers are hung with metal shoe on both sides of the ope and the remainder of the joist is then hung from the trimmers. The piece of joist you cut out is then hung between the trimmers at 600mm or 610mm or whatever is required. In this scenario forget splicing timber it's a waste of time. It's metal shoes all the way! If you roofed the house from scratch you'd be supposed to use metal shoes so this is no different. Also is it a cut roof or a truss roof??? Someone mentioned trusses I think. Rule no.1 of roofing.................you NEVER cut a truss apart from the over hang! It's over the top maybe but it's still standard practice.

mikeycoz

cork2 wrote: »

It's their mess make sure they fix it! Generally you shouldn't slice anything in this scenario. You cut out the ceiling joist to the required length, for arguments sake it'd be roughly 1200mm and you fit a trimmer on either end. The trimmers are hung with metal shoe on both sides of the ope and the remainder of the joist is then hung from the trimmers. The piece of joist you cut out is then hung between the trimmers at 600mm or 610mm or whatever is required. In this scenario forget splicing timber it's a waste of time. It's metal shoes all the way! If you roofed the house from scratch you'd be supposed to use metal shoes so this is no different. Also is it a cut roof or a truss roof??? Someone mentioned trusses I think. Rule no.1 of roofing.................you NEVER cut a truss apart from the over hang! It's over the top maybe but it's still standard practice.

My thoughts exactly.I remember the guy from a truss company telling me the computer calculates the strongest combination with the least amount of timber, to save weight.