How do you support roof to install new bi-folds?

[ptyltd]

Hi Folks,

OK, I need to install a new bi-fold door into an existing wall (refer attached D3) and wondered how to support the roof whilst I frame up for the new bi-folds? Doors are ~2500 wide so not huge but I will need to remove around 5 studs in the existing wall so I assume I will need to brace/prop up the roof while I do this (although I don't think there is a huge load on the wall as per the attached but hey, what whould I know - I aint no engineer ).

Can I just use a couple of props and a heay duty board under the bottom of the rafters (i.e neer the gutter so I don't have to remove soffits etc.)? As I need to cut out the studs etc. to get the new lintel and studs in at each end I don't think I can support the top plate directly so wondered how it should be done.

Thanks in advance.

[aussiecolector]

The way I've allways done it in the bush is pull the lining off the inside. Get a bearer that looks strong enough maybe 250 x 50, long enough to go between two studs that you are keeping. Without cutting the studs right through, mortise the bearer into the studs at the hight you want it, add an extra stud at each end to hold it up, then cut the unwanted studs out level with the bottom of the bearer.
This mite not be right but it works for me. No props required.

[ptyltd]

You might want to run that by me again aussiecollector, I am having some difficulty working that out:confused:

Existing walls have 70x45mm studs, you want me to check something sturdy into these across the whole span (how many mm into the studs?) at a height where when you cut off the studs this is the top of the new lintel yeah? I then put the lintel under the bearer (or sturdy bit o wood) and then put the new supporting studs in at each end. Doesn't this mean that as the supporting beam is xx mm into my 70mm I am going to have to check all the new studs around this as well?? Wouldn't you then sort of weakenthe structural integrity of the studs?

Sorry for the confusion and thanks for the reply I am just not quite sure I have understood.

[Harry72]

Hire some "acro" props and put 2 each side of the wall about 300mm from the wall then put load bearer's accross each set of acro's and jack the ceiling up just a tad to take the weight(stress just a tad... like 1mm or less).

If your not repainting the ceiling put some form of protection on the bearer's as any movement will scratch the paint, its advisable to fasten the acro's top(to the bearer) and bottom plates(to the floor) with some nails so they cant be pushed over... I've seen it happen, not a pretty sight!
If you have a tiled floor put some sand bags around them, also put some non-slip rubber under the acro's bottom plate.

[aussiecolector]

Sorry never delt with a wall that thin. Might not work. Might work if you can find a beam good enough 40mm thick, 30mm will hold the top up till you get the new beam up. What is on the outside? Is it an internal wall? Is it a load bearing wall? or is it only holding it self up? New studs dont have to be checked around bearer, except to hold them there, as they only need to finish at the bottom of the bearer. I hold the new beam op against the exposed studs and mark where they have to be checked incase things aren't quite straight.

[Ian007]

The first thing a bloke would need to know is what type of construction, is this a truss roof or a conventional roof?

If its a truff roof then that should be easy, if its a conventional number then the corner to the Lhs of the doors will be load bearing, probably with a hanging beam or the like.

get into the roof take a picture or 5 of this area and then we will be able to give you a much better idea.

Cheers Ian

[ozwinner]

You need to install a beam above where the new door is going to go BEFORE you take anything out.

Take off the plasterboard.

Check into the exsisting studs above the door, leaving clearance for the door, fit laminated beam.

Studs will be 90/100mm, beam will be 40/50mmx180/200mm, cut only to the size required to fit beam

Add another stud at both ends of the door opening, so as to make it double studs.

Remove studs in door opening by cutting UNDERNEATH the beam.

Simple

Or sling a chippie $400 cash to do it for you, at least you will be able to sleep without worring if its going to fall down.


Al

[ptyltd]

Hi Folks and thanks for the replies.

Have attached a couple more pics to further explain the situation. One shows how I intend to frame up the new opening (as I have a nother 2 doors that went in a new wall), One shows an external view of where the new door is going into the existing opening whilst the last one is an internal view of the wall that needs to take the door.

The corner of the house is a conventional roof (and it's a small hip so not huge wieght), the extension is of course trusses with a heay duty truss against the existing house (I am going to support the old rafters onto this and cut out some of the wall) and a couple of saddles back up into the existing roof).

Harry72, your suggestion was what I intended except I didn't know where to brace/support. I had thought proping up on the outside so I was supporting the rafters (and thus roof) directly rather than the ceiling.

Ian007, when you say LHS did you mean from the inside or out. If its left from the inside then refer comment about the extension and the fact there is a truss across from that corner. If you mean the other side then yep that corner is load bearing.

ozwinner, as before its 70mm (how uncommon are 70mm walls exactly?) studs and they have used battens to increase the size of the wall. Your suggestions sounds the same as aussiecolector which is what I don't quite understand. The new lintel is 170x45 and will be installed as per the attached picture (3 studs under and 2 jambs). I know I need to install the new lintel and studs into the existing space and had proposed to cut of the studs above the new lintel so whats left remains and become the lintel jacks, its just how to do it? Recommendation for a chippie whilst sound is not an option as I intend doing everything I am legally allowed to do on my own (so far has been a good learning exercise )

Is checking the new lintel into place and leaving 25mm on the existing studs enough to support the wall (otherwise how do you get in into position??)? Or do I prop independently as per Harry and then cut out the studs and fit new framing.

Phew - sorry for the long winded reply

[ptyltd]

I should also have said that on the internal wall photo the bigger window has been removed and framed to take the new extension wall (as shown on the external shot). The smaller window down the end will come out beacuse of all the studs supporting the new lintel.

[echnidna]

I'd forget about a 45mm lintel with 70mm studs. (specially if they're pine)
Look at the span tables and see what 35mm thick lintel width is appropriate.

Then just carefully cut away 35mm from the top end of the studs against the top wall plate. The lintel needs to be a snug fit but if its too tight don't bash it in, cut a bit more timber away.

[ptyltd]

Hey echnidna, the 45x170mm lintel is what was engineered and detailed on the plans etc. as well as all ready purchased and sitting out the back so that's what it is going to be. Interesting your recommendation is to have the lintel directly under the top plate, any reasons for this? I had planned to have it directly above the door as per the attached photo of the framing for one of the new doors (so door frame is fixed directly to lintel).

[ThePope]

what aussiecollector advised is the way to go...

Check out the existing studs to suit the size of your new head. Is simply a matter of setting your circular saw to the thickness of the new head (45mm) and running a series of saw cuts across the stud roughly 10mm apart, knock out the waste and finish off with a chisel. Pop the new head in and add your studs to either end. Nail off the "lintel jacks" and cut through them under the head with a handsaw.

Having little meat left on the lintel jacks doesn't matter a damn, all they need to do is transfer the load onto the new head. From the look of it you've got 70mm stud and 20-25mm batten which means you can use 90mm studs to carry the new head at each end. Unless you have odd regs up your way, you've gone berserk with all the opening studs on your new frame, one stud under window head and one full length stud next to it is adequate. Add more if you feel the need though.

Your dealing with little weight with a tin roof but to be safe it won't hurt to get one prop in the centre of the new opening while you fit the head. You'll need to remove part of the eave to do it, if careful when removing you'll be able to reuse it.

[ptyltd]

Ahhhhhh ThePope, it's amazing what a difference a picture makes (and thanks). The way you have shown the prop means it sits beside (not in the way) the wall and still supports the top plate. Is that right? If so then that makes sesnse and I got not issues using 2 props to support the wall and than checking the new lintel in at 45mm from the outside of the wall and then putting all my studs in before opeiong up the doorway.

Engineering specification was 3 common studs each end so the 3 under was my interpretation of that (actually I think I asked here as well). Not sure why I went with the two jambs but hey, better to go over than under spec (actually I have probably gone over on all my tie down etc.). Engineer even specified 2 common studs each end for a 1400 window as well so go figure.

Allready have the 70mm framing timbers so it was going to be a 70mm wall because I will get rid of the battens and nog out the studs.

[ThePope]

Yes the top plate of the acro goes underneath the wall top plate. Prop from the outside and cut your new head in from the inside. Otherwise the prop will be in the way when trying to slide in the head.

You're removing the battens eh, how's that going to effect lining things up with the existing cornice. From the style of cornice you have I'm guessing you don't won't to disturb it.

[ptyltd]

OK - Scratch removing the battens (DOH!! - had forgotten about the cornice etc.) Guess I am packing out the new frame work with the battens that will be removed from the opening.