Looking for some feedback on a planning issue we can’t seem to agree on here.
We are planning the procedure for framing a shed dormer on the back of a 10 pitch house, customer wants the dormer to span whole length.
We are not in agreement as to the proper procedure to open the existing up and begin putting in the walls, plate and rafters for the new, concerns of structural integrity come up. I have ideas, but was wondering what you folks have for thoughts.
THanks.
Replies
Tell me what your concerns are so we can start from there. I framed one about 3 weeks ago. The one I framed we had to also extend the front rafters up 5' to create a pitch high enough on the dormer to use shingles.
The existing ridge was sagging 2-3/4" and we lifted that up level and added new 5' rafters to the existing ridge and then worked from there.
Do you have to add floor joists?
Do you have enough man power?
Are you concerned about supporting the existing ridge once you ripped off the back of the house?
Brand new framing, 2 x 10 rafters, 2 x 12 ridge. 10/12 pitch, concern about the possibility of leaving as many of the original rafters in place as possible to hold up the other side. How would you approach the removal of the rafters. My theory is to remove only some at a time, essentially building the wall in sections, also it would seem that one could build support under chosen existing rafters, bearing down on bearing walls below (assumptions here about bearing wall placements) -- of course the stairwell hole is in the center and follows down to the cellar, so it would seem, that would serve as bearing.Then tie these in with an LVL placed under the existing collar ties. Ceiling joists will be placed to tie front rafters to back. Floor joists are already in place with existing attic space.
How far is the whole span?
10', 20', 30'?
You can support the existing ridge and ceilings with temporary post and beams if you have the room. Then remove any rafters that you need to.
This is just a shed dormer where you need to remove all of the back rafters of the house. This type of job is done every day all year around. The problem with the winter is daylight. What has me concerned about you is your Framer.
You say he is experienced and yet he sees the negative in everything and gets hung up on ideas. That doesn’t seem like he’s experienced with doing a job like this. If he's framed many shed dormers like this than this one shouldn't be a problem at all.
What he needs is experience with dormer jobs like this. He could be an experienced framer and frame any house you put in front of him with all NEW work. Working on existing homes is night and day and doing remodeling or additions and ripping roofs off of houses is a whole different way of handling the framing.
What would he do if you presented him a blueprint that has a complete second story Add-A-Level to frame right now?
I'm not here trying to bash you or anything it just that everything you wrote so far tells me that your framer isn't experienced enough to handle this Dormer job and he doesn't have the man power to do it right and keep this house WATER TIGHT which is the most important thing to do.
If you can tell me what all his concerns are and if you can be honest with me and tell me how many of these additions he has done and he's looking for advise that's fine also.
There’s ways of doing these jobs if you don't have enough man power. So I can give you ideas of how he can approach that. If you have a big enough crew you can have the roof ripped off and the outside walls and rafters framed in one day tarped and water tight
Usually on jobs like this the ridge has a sag in it. Either you jack the ridge up straight or you leave it alone. If you leave it alone and don't want a level ridge you will have to cut all your new rafters all different sizes. One at a time or you cut them all the same and then cut the plumbcuts on the scaffold for them to fit Or you put the two end rafters on and string a line at the top of the rafters to keep them straight and nail the rafters to the line.
If you don't do that and cut them all the same they will be sticking above the ridge. If you don't have enough man power and you said that you don't have to add floor joists because they are there already, you can cut a whole in the roof at the ridge enough to nail new rafters in and where your joists and rafters are at the top plate cutting the roof out enough to nail your studs on the top plate into your joists and then put blocking in later between the studs and the joists and frame a section of the back wall and new rafters. This way you don't have to take any of the roof off accept the little sections at the top and bottom to nail your studs and rafters.
If you do it this way you can start out by cutting a hole right at the corner of the top plate and ridge and nail a 2x4 plumb and braced and while your doing that the other guys on the crew will be cutting out the rest of the roof and cutting studs headers jacks and sills. These can all be precut the day before you even start the rip off. Once that stud is nailed and plumb then you can bring over a rafter and scribe the birdsmouth and plumbcut and then whatever overhang you want to get a pattern. This can all be done before you start also. Just go there and cut the bottom and top corners only like I said and tack the stud in plumb and get your rafter pattern and then patch the small 1’ or so section with snow and ice or plastic and then go cut a section of rafters and studs, headers, jacks and sills. Then the next day your ready to go and not have any time wasted doing all this with an open roof.
If you don't and rip a section off including the rafters, you will have to either cut back 1-1/2" on the 2x joist and add a continuous box/rimboard or cut blocking in between your floor joists because your floor joist will have a slash cut with the rafter angle on it so you have do this to give you flush and solid nailing for your decking. Then you can nail down a shoe and frame a wall and section of the roof and tarp.
If the ridge is really bad and needs to be jacked up, removing the back roof first is your best option because you wont be able to put temporary walls in and jack it up easy with the back rafters on.
Just give as much information about your framer so that we can help because doing jobs like this does have to be properly planned and does need an experienced framer. This could be his first dormer which is great because we all started out doing our first dormer or add-a-level at one time and needed guidance so give all the info you can.
Joe Carola
Edited 1/23/2006 10:04 am ET by Framer
This is brand-new frame, so everything is up to code and straight and plumb as can be expected.We were discussing this this morning and planning on doing all the cuts first was the idea, including headers, etc. Like any other frame-up have the cutter cut it all the day before.Definately, when discussing any cut-in, timing is essential, having cuts done prior, having sufficient tarps, planning for weather, etc. We've done a dormer before and had no problem as we planned sufficiently.Here's what he is thinking:Remove plywood along bottom, stand up a wall.
Nail rafters on ridge pole, ideally opposite one another
Ridge can be shored if necessary, take rafters out and build dormer accordingly.As usual, he knows the answer himself but has to think about it. I thought I'd bring it up here and I can see his thinking is pretty much the same as everyone else here.His experience is varied over a wide swath, from residential framing and finish, to bridge building, to commercial finish. He doesn't pretend to have all the answers and has seen a lot of errors and is very careful. I am confident that he'll ahve this figured out, also we have others to confer with if necessary.I can see from your feedback, that as I had always thought, he worries thinking there's some answer or way that he doesn't know. I guess, to ask and be open to learn is nothing bad, but his hesitation when he has the answers right there in his drives me crazy.I had to get him to read your posts so he could see that he is able to break these jobs down. We've never yet run into a job improperly carried out, so I have confidence in him and this has strengthened it.thanks. I'll let you know what comes of the job, if anything at all.