I am just getting started on sheathing the roof on my new construction spec house. No windows or gable sheathing installed.
And… here comes Hurricane Isabel. I’m in the Philly area and we don’t get much hurricane weather here. I’m wondering what to do: sheath and paper as fast as I can or wait it out.
Does anyone out there have any experience along these lines? I think I remember a Discovery Channel show on hurricanes saying it’s best to leave some windows open when they approach which would seem to indicate it’s ok to proceed.
I really don’t want this home to lose its roof.
Thanks for the help
C
Replies
If the house isn't sealed up yet, I'd wait. Wind will enter the building through the window and door openings and could blow the roof clean off - this is how most roofs in hurricanes are lost. But there's a trade-off that you might not get much wind, but a serious amount of rain, which causes its own problems.
I guess it really comes down to how much wind you'll have, something we can't predict. If you do decide to sheath, buy some hurricane clips to tie your roof to the walls just in case.
Look, I don't have any great insights into your problem, but I feel your pain. I can't help but think that if the winds are high enough to rip off the sheathing, they will rip off the rafters anyway. But I could be wrong. If you have time to get it fully sheathed, and all your Simpson ties on (you were going to use hurricane ties, right?) I think it would be o.k., unless complete disaster strikes. Otherwise, I think you better brace the everliving hell out of the roof framing and pray. Don't skimp on the sheathing nails, and I don't think I would waste time papering the roof.
So to summarize: I really don't know.
Wind will put some number of pounds per square foot on the structure. With the sheathing on, you have lots of square feet, resulting in more load than you'd get on the bare rafters. Dried in would be best for rain, but bare frame would fare better in high wind. Unfortunately, you have both coming, so you just have to pick your damage.
-- J.S.
CW...I`m in the exact same boat and had planned a similar thread. No chance I`m gonna be wrapped in water tight before Thursday....wondering whether I should even bother poppin` the rafters in at all. Looks like I`m damned if I do, damned if I don`t!
Best of luck to ya brother!
J. D. Reynolds
Home Improvements
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I'm really just speculating, but I think you'd be better off to wait. In Andrew, lots of buildings were lost when windows broke or gable ends blew in, letting in the wind which lifted off the roofs. With your building wide open, no soffits, maybe no facia yet, I think the roof is even more prone to lifting off. If you're thinking that getting the sheathing on might be better to protect from rain, I think with hurricane force winds, blowing rain through window and door openings would have everything soaked anyway, so I think you'd be risking loosing the roof for a benefit you really wouldn't get.
I'd make sure your trusses or rafters are securely diagonally braced (you can remove bracing later), and all your hurricane clips holding the trusses down are already in place.
Also, make sure the site is picked up and secure. All you lumber and plywood is securly tied down or stacked in the basement, but high enough to not be flooded, etc.
Your plywood may walk away after the storm. Maybe some sturdy chain and locks are a good idea. You may not be able to get replacement material so easily.
I think WAYNEL5 has the right idea. Brace those trusses. Down here in Florida it is pretty much standard to install permanent bracing for gable ends. Usually two 16' long two-by-fours meeting at the peak and fastened parallel to the sheathing going down to the side walls. These are nailed in inside the trusses with 2-16d nails at each truss.
One local contractor tarps the floors with big blue tarps and cinder blocks if heavy weather comes near but I hear you need to take the tarps off within a day or so after the rain otherwise the heat of the sun and the little bit of water that gets through can cause problems. Seems to keep the floor mostly dry. It is less effective when the walls are up but it still helps.
I have seen at another carpenter crew spray on some sort of sealer. Looked like industrial deck sealer. I'm not sure how well that worked and suppose it could cause problems with some flooring options.
A poster on this forum once suggested drilling a few holes in strategic locations to prevent ponding.
These seem like good ideas but then again I'm just an electrician and I tend to be out in any storms trying to repair damage from tree falls. I once completed replacing a riser and was driving out when the police told me the area had been evacuated for four hours. I thought the wind was a bit strong while hanging on with one hand and working with the other in the horizontal rain. Sometimes ignorance is the strongest defence.
Brace the heck out of the roof and brace the gables to the floor.
Lots of diagonals across the spans.
Attachments in next post.
SamT
Edited 9/16/2003 1:11:50 AM ET by SamT
Attachments
One phrase might answer the question..
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Be just framing
andy in NY
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Guess I'm the only one who thinks you should put the plywood on.
The plywood gives the roof structure a tremendous amount of strength. Basically makes the roof like a big airplane wing, which doesn't need much added bracing.
Without plywood, you basically have a bunch of toothpick flapping in the wind that will require a heck of a lot of bracing. As they wiggle back and forth in the wind, they can work the braces loose.
If your hurricane straps are in place, and the walls sheathed, I'd do it. But I'd use plenty of fasteners - Maybe even screw the plywood down if the codes allow for that.
I see by the map that someone provided the other day that the max sustained winds are down to 115 MPH. That's certainly good news.
http://www.wunderground.com/tropical/tracking/at200313_5day.html
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just got to worry about the gusts that can go to 70% above the max sustained wind speed !
Thanks for the input, guys.
My framing is pretty solid. Stick built 2 x 10's 16"oc and a total span of just 22' so there's not as much movement as with trusses.
I guess I'll try the middle ground and lay one course of sheathing to tie the rafters together and hope for the best. Get the hurricane ties on and brace here and there.
No worries about the basement filling with water as it's a ground level (drive in) basement.
Hopefully I'll have no disaster photos to post next week.
BTW It's really difficult to make any decision based on our local weather forecasters. They just love this sort of thing and have been foaming at the mouth since last weekend. And, they're prone to crying wolf when it comes to "KILLER STORMS"
C.
Guess it's natural for the weather guys to get as excited over weather as we get over power tools and fiber cement. It's their life.
Isabel is not a small storm, however. It's had the highest wind speed recorded in a hurricane -- ever. It's down to "only" a category 3 now, but I don't think it's wise to dismiss the forecasts as hyperbole.
I was on vacation all weekend so missed the point when Isabel had such high winds, when was that? All I could find was a max of 160mph, and I know that Gilbert, back in '88, had sustained winds of 184 mph, gusts well over 200, and a pressure of 888 mbars which is the strongest Atlantic storm ever.
It was on the radio a few days ago. ABC News. I don't remember the day, but the story was about the aircraft crew recording the highest wind speed ever recorded in a hurricane. It's good the storm is weakening from the peak.
http://antwrp.gsfc.nasa.gov/apod/ap030916.html
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I'm with the "Boss" plywood will strenthen the roof. You can add extra lateral bracing on the inside of the trusses and make sure your hurricane straps are on."It doesn't take a lumber jack to climb a fallen tree"
Marv