I am a remodeller that does kitchens/baths very small additions and wine cellars ( I haven’t done a 2nd story addition myself) I’m currently in planning stages for my own home. I’m going to add a 1/2 story above, ie keep same footprint but increase the pitch on the roof which will have a couple dormers out front and a shed roof off the back.
My question is: Is it possible to do this without too much disruption to our current drywall ceilings? – House width is approx 26 feet. I was thinking of getting web floor joists to span exterior wall to exterior wall and then cutting out current roof rafters and replace.
Sound reasonable?
Thanks in advance for any input!
Brad
Replies
sounds reasonable... do the existing ceiling joists span from the bearing walls, or are they connected to the rafters? are the new floor joists above the existing ceiling joists or are the sistered to them (and closer to the drywall below?) Is there any ductwork or recessed lighting in this space?
do the existing ceiling joists span from the bearing walls, or are they connected to the rafters? are the new floor joists above the existing ceiling joists or are the sistered to them (and closer to the drywall below?) Is there any ductwork or recessed lighting in this space?
The ceiling joists span from the bearing walls and are a one piece with the rafters. I would put the new floor joists above the existing ceiling joists ie build up the external wall height and use a lvl rim joist
There is minimal duct work, only one return and a few recessed pot/can lights.
in that case, yes, it sounds like a good strategy!
brad.. the devil is in the details.. i assume you are going to try to leave the existing roof in place to protect the first floor
to span from wall to wall requires a very deep web ( 26' span ), and you are going to install it ON TOP of your ceiling joists... this adds about 3 extra risers to yur stairs
so to get them in place you open up the eaves on both sides of the roof for a couple feet
then you manhandle them across, sliding them in... but there are lot's of things in the way.... especially wires... maybe a pull-down stair frame, some plumbing etc
then , you have to get a new subfloor in , which has to come thru the house.. or thru a big hole in the gable end or the roof
each time you open one of these holes you have to protect the 1st floor
... ok.... now you have the new floor system in place and the subfloor
you can leave the existing roof in place, and build a new roof over the top , as long as you have access to the plate .. and of course you install the new rafters alongside the old rafters
then you sheath it and water proof it and remove the old roof from the inside
there are three ways ( really four, but i'll get to that )
one... you get a lot of tarps and every night you tarp the whole thing , and pray for gentle storms.... big wind storms are almost impossible to protect against..... a 20' x 40' tarp has 800 sf of sail area
if you strap the tarp with furring strips , then you punch holes in it which leak... so .. if you get lucky , you will spend a lot of time and labor protecting the first floor
and ..... it wil take you twice as long to creat the floor system and the roof.. ( nothing to do with the protection... that's over and above the twice as long part )
the second system , which i've seen done twice now .... is yu build a structure with pipe staging completely around the house, then you install temporary trusses over the pipe staging and cover it all in the plastic they use to protect boats ( shrink wrap ).... then the trades can work in any weather and finish the 2d floor
the rental on the pipe staging and the temporary truss roof costs almost as much as the whole 2d floor addition
a third method is cutting the whole roof system free of the plates.. then either jacking it, or lifting it with a crane and tilt up the new walls, install the new floor system , then refasten the old roof to the new plates
the fourth system ( which is now my favorite ) is to resign yourself to losing the ceiling and having quite a bit of damage to the first floor, tear off the old roof, throw it in a dumpster, now , working on a bare first floor ceiling with no roof... build in a conventional manner
there are stil modifications yu have to do to the first floor, including comming up with space for the stairwell from the first floor to the 2d floor
systems one and three require a lot of luck
system two requires a lot of money
system 4 is pretty foolproof
Edited 2/26/2008 3:20 pm ET by MikeSmith
Mike thanks for the input and the other options, hadn't given 2 & 3 a thought.
4th is the plan currently, but wanted to know if the other has been done with success. I know - Anything can be done with time and money. Both of which are in short supply for this project - especially the former.
More info and opinion welcome!
Brad
Option #5. Pre frame all the walls. Have trusses and floor trusses handy. Hire crane. Chop roof. Set floor trusses. Set walls. Set roof and sheath. Put felt on roof. We did an 800 sf second story like that in a 8 1/2 hour day with four carpenters, one roofer and his three laborers. The roofers and laborers worked about a 5 or 6 hour day. Anything is possible. I like Mikes approach because it will work for anyone. Our method might be intimidating for crews that haven't platform framed or are timid about preframing all the walls. Heres in Austin, I am encountering some sites with heavy tree limb encroachment and Mike's solution will be an excellent option on those sites if the existing home needs saving. Thanks Mike! Now...lets talk about that 26' span. Do you really have to span that far? What happened to your interior bearing points? Heres a tip: block up. Block up your new floor system at least one plate (1 1/2"). This will be critical to clear a lot of obstacles and protect the ceilings from cracking. Bob's next test date: 12/10/07
Well I definitely have to span that far in our open concept kitchen, dining and living room. There is one bearing wall that I can use on the bedroom end of the house, just about half of the sq. ftg.
Thanks Jim
have to span that far in our open concept kitchen, dining and living room
Ok, that triggers the "consult an engineer" reflex.
Not that your proposed scheme might be lacking, but more that the existing walls and foundation are up to what you want.
In some ways, you are making the outside walls "taller" with respect to lateral forces, and that "hinge point" at the top plate can be an issue. Since you are spanning the structure, you are creating a parallelogram that might want some stiffening.Occupational hazard of my occupation not being around (sorry Bubba)
I am assuming I will have to sheet the ext walls anyway, as there isn't any currently, only 2x4 stud, paper and lap cedar siding. Have an appt with engineer next week. Currently, I'm just looking for some re-assurance from some more experienced folks that the "plan" could be okay.
Thanks.
Post a picture of the "plan" and we'll okay it. Snap a digital picture of the plans if you don't have them in PDF format. Bob's next test date: 12/10/07
Well, if the room is 26' by 26' wide, than I agree that your span has to be 26'. The truss manufacturers can span that far. The trusses are heavy and I would use a crane, even though I've set longer spanned floor trusses by hand. I'm smarter now than I was. Bob's next test date: 12/10/07
It's very possible, add a plate on top of your existing ceiling joists. Then use 18" clear span floor trusses. Add your strongbacks to them and sheath the floor.
Precut all your rafters so when the last sheet of subfloor os laid down you can start nailing in rafters.
Matts Garage in the photo gallery should show you what I did to my garage. Might give you some ideas for your project.
Woods favorite carpenter
Thanks Matt -good pics and nice to see the timeline too - gives some hope that a "barn-raising" can still happen!
Brad,
I would vote with Mike Smith's 'System #4' but instead of building right away we first do the following.
Block between every other joist space on both sides, if the top of the joist are cut away to much (original roof slope was low) we add 2x4 studs same as joist height.
Add new joist both ends of building, block back to first existing joist (blocking 24"OC min.) Nail single plate on top of new joist both ends.
Block every other set of joist above existing bearing wall. Nail single plate down center above existing bearing wall.
Plan view now shows large ' I ' of new single plate material.
Unpack two 30'x50' (or appropriate size) tarps spread on open lawn one on top of the other and roll into 30' tube and haul it on to the top of the existing joist.
Optional: Add plywood or 1x on top of existing joist, we usually don't, but it does help keep the water from puddling so deep between joist.
Pull enough tarp over the 30' edge to flash over the top of the 1st. floor siding and nail. Start unrolling the double layer tarp. After you've rolled out 16' stretch it tight and nail down a plate on top of the new blocking and cripple studs ( stay away from the inside edge so you don't blow a nail thru the tarp where it won't be pinched between piece of 2x.)
Look for nails, debris, splinters etc. as you unroll. To pad over a sharp edge just throw some fiberglass over it.
Also add your second plate on top of the first new center plate, and add your second plate on top of the new plate running the 30'
You can work right behind the roof framing tear off guys, or if you are the roof framing tear off guy you can stop any time and keep the 1st. floor dry.
Your tarp is now stretched over the whole building, leave it long and flashed over the existing siding , it drains between the unblocked joist spaces.
Plan view now shows plates as if you were starting the second floor deck on new construction. Start hauling joist up and building your floor, at the end of the day pack up your tools and go home, no worries.
Be careful as you walk above the tarp and keep a tube of silicon or gutter seal handy for repairs. The tarp does not get cut until the stairway goes in.
Regards Rich
I took one of these on recently having never done one before. I hired some extra help for the initial days. first day we cut roof plywood (shingles still on - 3 layers!) into manageable pieces and pitched into dump truck. second 2 man crew followed behind cutting out rafters. we left the ridge in place and the end and middle set of rafters for support of tarp. third 2 man crew cut back ceiling joists to allow for new rim board and then ran 2x6 plates around perimeter and down center. tarp for night. that was day one. second day we pulled final rafters and ridge, framed floor system using a laser to level the middle (old bearing wall in 1st floor had issues). while framing, had plumbers run pipe for baseboard heat. Electrician stopped in to drop a bunch of home run wires to basement panel. then we sheathed the floor except for stairwell and basement. put saw horses in middle and re tarped (gives pitch to tarp.)
third day 1/2 crew framed exterior walls, 1/2 crew started cutting rafters. got walls up and main ridge with couple rafters. fourth day - put up intersecting ridges (cross gable) and finished rafters. started to work on filling in valley rafters and jack rafters. this was the hardest to tarp at this point. I like to tube idea mentioned earlier. fifth day, finish jack rafter, sheath and tarpaper/ice and water. then we finished gable end framing ad interior framing at more relaxed pace with just my crew .good luck - ps bad weater comes out of no where the minute you finish demo on the roof =-)
jason
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It's the feeling of falling further behind."
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