load-bearing walls

[Trav]

I know this must have been asked before, but I did a search and didn't find anything entirely relvant.

I have a 1969 brick-veneer house in Canberra. I want to knock out a few internal walls to open up the kitchen. From the plans, it appears that the walls are not load bearing, but when I get up in the roof cavity, there is an awfully large number of struts between the roof beams/joists and the actual timber frame of the roof.

Is there a tried and true way of working out if a wall is load bearing?

Apologies if this is crossing old ground for this forum.

Trav

[silentC]

Hi Trav,

You are probably talking about the underpurlin props which are there to stop the rafters from sagging. The underpurlin is the member that runs at 90 deg. to the rafters and the prop is fixed on an angle between the underpurlin and the wall top plate. You can't take those walls away without making allowances for the props. It's probably a good idea to consider getting a builder in to do that. Depending on the size of the opening you want to create, you might just need a lintel or a beam, or the prop could be moved to another wall.

You might also have a load-bearing wall where a hanging beam sits on it. These beams run at 90 deg. to the ceiling joists and again you can't remove these walls without replacing them with something or redesigning the ceiling structure.

The rule of thumb is that if there is a prop or a beam on top of the wall, then it is a load-bearing wall. If it's not a load-bearing wall, none of the roof timbers should be in contact with it.

[Trav]

thanks SilentC. Sounds like I need a builder. There is a dead-set forest of timber in my roof, and it seems that everything is connected to everything else. What a pain.

Not sure if it is appropriate, but can anyone recommend a builder for smallish jobs (hopefully anyway :)) like this in Canberra?

Trav

[echnidna]

Play it safe and get a builder to have a look.
Last week the newspaper reported about a goose in the UK who removed a wall in his flat but then his upstairs neighbors bathtub fell through the floor and almost brained the clod. To add insult to injury he ended up in court and got a community works order against him for his illegal works.

[seriph1]

I agree to seek info from a builder, though with the housing boom, you might have trouble - If I may say: a trap a lot of folks fall into is thinking they need to remove entire walls to make full use of the joined spaces. It can be simply that a bulkhead will suffice, coming down, say 20-35cms(no idea how high your ceilings are, but probably 8-9ft. What you do, if this was suitable is, cut in a beam (timber or LVL, depending on span) that supports the roof and IS supported at each end by double studs either in the remaining wall, or as a pair of small returns, if necessary.(its easier to draw than explain!)

This way you enjoy added space without major work being needed inside the roof - also, I feel there is the added benefit of being able to have the larger space, but with a "delineation" point where the short-return-walls and the bulkhead are....allowing for some decorative corner brackets, fretwork or the like to enhance the room where appropriate.

end of sermonette :)

[Trav]

cheers Steve

Getting a builder will be a good trick in the current boom. Canberra is/was really surging. We are looking at getting a new kitchen and doing a few other things, so it might be possible.

As for a delineation point, I would ideallly like to avoid that. At the moment, one room is too big and the other too small. This means that my dining table would ideally be sitting right where a wall is at the moment. Having a bulkhear with the table under would look a bit peculiar. Mind you, if it saves me heaps of dough, I would probably get to like eating under a bulkhead...

Trav

[seriph1]

understand totally - but done well, they actually enhance a space - just have to make sure your design is right.

Once the design is right, consider the savings:

1. no impact inside the roof - no "Stuff" to move
2. fewer plaster repairs - ie: cornice(possibly)
3. Possibly DIY - with a little help = lower outlay + new learned skill
4. Bulkheads "disappear" to all but a few people
5. Bulkhead can receive a plate rail or similar shelf for display items, making it actually a benefit to the area.

and other things I am sure we could come up with given the correctly metered application of alcohol


If you feel it would be helpful I could dig up some examples from my design library, but I would need a cpl of pics of the space

[jimmyjames]

Hey there,

I am a reno novice and have just gone through this exercise myself removing an eighties archway and part wall between lounge and dining room.

I tried to get a builder to do it with no luck - too small a job I suppose. In the end I got a carpenter mate (he couldn't do job for me due to a pregnant wife) to ensure we had a truss roof and I just started hammering.

The wall in question was connected to the rafters by a top plate nailed to the rafters using brackes. I presume this was to stabilise the wall. After removing the wall there was some slight movement of ceiling gyprock either side resulting in very minor cracking which has not spread after 2 months. I believe the gyprock was put in after the wall frame and this frame exerted some supporting affect on the gyprock. So though the roof won't fall in, taking away the wall did affect the ceiling.

As mentioned previously we left a bulkhead between the two rooms. This was done to open the room up but still make it distinctly two areas - lounge and dining. (Also with the cracks in the ceiling appearing I panicked and thought I better get some support up there - my carpenter mate thought that was hillarious). We got a very cheap 190 *75 treated pine length and sat it on double studs supported at the bearer level.

We found the floorboards did not continue under the wall. I quickly learnt how to insert new boards and that problem was solved.

Finally I will be getting a pro in to gyprock around the bulkhead and studs. While there I'll be getting him to patch up the hole where the old flu used to be and the hole I made when I tripped in the roof and put my foot through the ceiling........did i mention I was a novice :)

It was all worth it. The room looks fantastic, hope your's turns out great.

[journeyman Mick]

To any/all that are contemplating similar work: not only do you need to watch out for load bearing walls, you also need to watch for bracing walls. Some internal walls take no roof load but act as bracing members to stop the outside walls from being forced in under wind loadings or to stop the whole house falling over like a house of cards. If it butts against an outside wall it may be a bracing wall. It pays to get a copy of your house plans from the council.

Mick

[dale]

You should also get a copy of the Timber Framing Manual, which describes beam sizes and general rules for constructing wooden framed houses.

Reading it can really show you how a house goes together, and what to, and what not to, do.

[bitingmidge]

Simple rule here...if it falls down you took too much away.

BE WARNED what you don't know CAN hurt you!!

Take the advice of all above, DON'T do anything until you have an understanding of how the structure works, and the Framing Mode is a great place to start.

No point working out the beam size needed to hold up the roof, the additional bracing if you are removing a bracing wall, the number of studs to add each side of the opening, (and there are many load bearing situations were "double studs" are not enough), if at the end of the day, the bit of floor or subfloor is inadequate to take the additional load.

Once you have an idea of what you are doing, get some advice from a builder at least, even if it is using the ruse of obtaining a quote. Gee I hate people who do that!!

None of the work required is difficult, just needs experience, skill and patience to achieve.

On the other hand if your roof is trussed and the wall is non structural the whole thing will be a doddle and all of the warnings will be in vain!

Go for it!

P

[silentC]

The wall in question was connected to the rafters by a top plate nailed to the rafters using brackes. I presume this was to stabilise the wall.

It's more likely that it was there to support the roof :eek:

Hope it's not a tile roof. If you start taking props away like that it could sag....

[ozwinner]

I think the bracket in questin is just a hanger.
I've seem these in houses with truss roofs, they only stop the free end of the wall from flopping around.
Cheers, Bob

[silentC]

Sounds like a dodgey building practice to me, Bob. Is that how the plasticine houses on your show are put together?

Seriously though, if it's a truss roof, there shouldn't be any timber connecting the walls to the trusses, cause they are s'posed to span from wall to wall and not touch any other walls on the way through. If it isn't a truss roof and it's an underpurlin prop then it's a load bearing wall and you pull it out at your own risk. It could be part of the hanging beam set up that holds up the ceiling, but they shouldn't be connected to the rafters either....

[dale]

Originally posted by silentC

Seriously though, if it's a truss roof, there shouldn't be any timber connecting the walls to the trusses, cause they are s'posed to span from wall to wall and not touch any other walls on the way through.

If I was building a house with a truss roof I'ld tie the walls to the roof even though it's only for rigidity.

If you had a 4 meter long wall that formed a corridor, the only way to stop it flopping about would be to secure it to a truss. The cornice is not going to secure it enough...

[bitingmidge]

If I was building a house with a truss roof I'ld tie the walls to the roof even though it's only for rigidity.

If you had a 4 meter long wall that formed a corridor, the only way to stop it flopping about would be to secure it to a truss. The cornice is not going to secure it enough...

Hmmm then you would be expecting the walls to bow just a bit when the roof load went on I guess?

If by "secure" you meant locate a cleat either side of the wall to creat a "slip" joint which allowed the truss to remain clear of the top plate when fully deflected, then you would have a perfect job!;)

Seen plenty of structural cornices too, and they usually have a life of about fifteen minutes after the last coat of paint has been applied.

Sorry if I'm being a smarty pants, but trusses are not designed for intermediate support, and there are a number of ways of tying the wall top plates using ceiling battens to stop them wandering, without risking damage through inappropriate detailing.

Cheers,

P

[jimmyjames]

Hi,

Well I've gone back over removing that wall and still think we we're ok. Hope I haven't hijacked the original post but for anyone interested here's why I think there was no load on the wall we removed.

The brackets used to secure the wall to the rafters were very lightweight as was the timber top plate. If these were supposed to hold weight I would have expected sturdier construction.

Having an archway in the middle of this wall meant there was no consistant frame throughout, I think it required some support from above to help support the arch and to stop the wall from moving.

There was no bracing or prop meeting the rafters directly above the top plate.

In another part of the house there is a span between walls equal to what there now is in my loungeroom. There is no difference in the roof trusses between the two areas. This suggests the trusses are able to sit above that span with no probs.

When the wall was gone we found the stud where it met the external wall was swinging in the wind - not connected to anything underneath, only being held up by the top plate and a nogging. If this was load bearing I would have expected that to show before now.

My qualified carpenter/builder mate agreed with all this and in any case there is now a bloody great beam bolted to the underside of the top plate sitting on double studs which are supported on the floor bearers.


How else would you secure a wall in a house with a trussed roof? Would cornice be enough? In regard to the inner wall supporting the outside wall would another wall butting up to the outside wall 3m away do that job? Any other feedback would be welcome.

[ozwinner]

Originally posted by bitingmidge

and there are a number of ways of tying the wall top plates using ceiling battens to stop them wandering, without risking damage through inappropriate detailing.

Cheers,

P
Ceiling battens?
I havent seen those used in Vic for many years, unless you are haveing a tin roof with trusses at 900mm centres, then its only the tin type of battens, which wouldnt hold anything.
Cheers, Allan

[dale]

Originally posted by bitingmidge
Hmmm then you would be expecting the walls to bow just a bit when the roof load went on I guess?

If by "secure" you meant locate a cleat either side of the wall to creat a "slip" joint which allowed the truss to remain clear of the top plate when fully deflected, then you would have a perfect job!;)
Seen plenty of structural cornices too, and they usually have a life of about fifteen minutes after the last coat of paint has been applied.

Sorry if I'm being a smarty pants, but trusses are not designed for intermediate support, and there are a number of ways of tying the wall top plates using ceiling battens to stop them wandering, without risking damage through inappropriate detailing.

Cheers,

P

How well it works depends on the type of connection you make between the truss and the top plate, and also on the type of truss you have in the roof.

You can get angle brackets (i'm almost sure of) that you nail securely onto the top plate, and allow vertical movement of a truss.

It also depends on the type of truss that you have in your roof. My parents house has 3 trusses in it, which run the -length- of the roof - one for the center ridge, and two either side at the mid point of the slope. They are certainly tied to the top plates. It's quite a nice design actually - it's quite easy to move around inside the roof, and still provides strength for large open internal spaces.

I know that cornice wouldn't hold anything - I was just making a joke :-)

[silentC]

Trusses are designed to span the walls on which they sit and should not to be bearing on anything else in between. The way you are 'supposed' to do it is to use a batten on either side of the bottom chord of the truss like Biting Midge said.

If for some reason you are not using ceiling battens, presumably meaning you are fixing your ceiling directly to the bottom chord, then you'll need to find some other way that does not involve securing the top plate to the truss, perhaps the brackets that Dale mentions. I hope your trusses are nice and straight.

Jimmyjames, all I can say is that hanging a top plate off a truss to support an archway sounds dodgey to me but if your roof is a trussed roof, then it's not going to fall on your head if you removed it. It is a trussed roof, right? You mention both rafters and trusses in your posts.

[jimmyjames]

My last post on this I promise!

Yes it's a truss roof - my builder friend has been inside the roof and made sure of this. If I used the wrong terminology I'm sorry, I meant the underside of the roof frame / truss as opposed to a rafter. I put the N in novice I can assure you but I never would have touched the wall if I wasn't told it was a trussed roof.

Thanks to all who replied and sorry if i hijacked the post.