home protection question

[RB]

Went though Ivan and now Dennis without significant house damage. However, other hurricanes will most likely be along. And, they seem to like where I am on the Gulf Coast.

Got a concern I'd like your opinion on. I believe losing your house roof during the storm peak would be a major casualty. This possiblity bothers me a lot. So, I started trying to think of simple and practical ways to minimize the likeliehood of this happening. You've got a miserable time ahead of you if your roof goes. This and a big, heavy tree falling on the house are the two big structural casualties I see associated with these hurricanes.

One idea is to throw ropes up and across the roof at several points, and cinch them down to opposing auger ground anchors like mobile homes use. These anchors are not too intrusive or obvious, and the ropes can be stowed except for use during storm times. Three or four ropes would literally tie your roof down, except for where the ropes aren't. However, I think the roof is interlocked enough the three or four ropes across it might fairly well hold the whole thing on, if it was attempting to rip off from wind blast.

The question being: is this approach likely to give your roof the edge in staying down when it might otherwise blow off? In other words, even though the rope approach might be a marginal thing, could it be that the marginal downward holding force might just be enough to make the difference between keeping and loosing the roof in some situations?

We know that under certain conditions, the roof can blow off no matter what we do. But, I'm just wondering if there's enough of an edge to this idea to make it worthwhile doing? Probably $100 for a coil of manila rope and some ground anchors would be the project cost.

I guess my concern is that we might get a stronger storm than Ivan was, and/or a very slow moving one which would have lots of time to progressively weaken the roof attachments.

[gfretwell]

How old is your house. The current Florida code (and really anything in decades) gives you many times the uplift strength you could get with ropes and RV anchors. You might lose your shingles but the trusses and plywood should stay for anything but a 4 or 5 eyewall hit. Your ass is grass then anyway.

[Joseph Meehan]

Get a trusted local contractor to take a look at your current construction and make recommendations to bring it up to current code. Following the standard practice (I believe that means adding metal brackets inside that help hold each rafter to the side walls) is by far the best solution.

[Steve B.]

The mobile home straps are designed to stop the entire home from flipping over in a strong storm and you want to keep the entire roof from blowing away so at first glance it seems like a good idea but..

Generally you don't loose your roof as a whole unit in a hurricane. What happens is the wind gets under the roof when something gives. Once the wind is under the roof it literally rips it all apart piece by piece.

The best protection you can get in my opinion is to make sure all the joists are firmly attached to the walls using the strapping method currently defined by code and make sure all the structure around the roof is substantial and well enough attached that it won't come loose in the storm giving the wind an opportunity to rip the roof apart. The new code is also pretty picky about how the decking has to be attached but you really can't change that without ripping off the roof.

Steve B.

[PipeDown]

You will have a good opportunity to reinforce the roof next time you reroof. With the shingles off you can add additional longer nails in the decking and add some metal straps to anchor the rafters to the side walls (may need to temporarily remove a srtip of decking to gain access but this can easily be replaced).

As for the odd tree falling, you can always fell them now when you are in control or at least trim any large limbs that might overhang your house or car.

[HeyBub]

1. Anchor roof according to plan, just in advance of hurricane.
2. Rain causes manila ropes to shrink 5-10%.
3. Roof is crushed downward.

After repairs to house with saddle-shaped roof, improve plan for next hurricane: this time use Nylon rope.

Nylon stretches 5-10%, causing roof to be lifted 2.5 feet and set back down at angle.

After repairs to now really funny-looking house, re-jigger original plan to use wire rope.

[kevin]

use wire rope.

Wire is kind of sharp, causing your roof to be sliced into nice thin strips, like a french fries run through a wire chopper.

[Apropos]

Sounds like some properly installed hurricane straps would be the BEST way to go.

In lieu of such a proper repair job, I'd trust the wire ropes more than anything. If roof-destroying winds WOULD have ripped the roof off, there's no way to avoid SOME kind of damage anyway.

Anything, however, sounds better than using ropes which might SHRINK, which could damage the roof even if the high winds don't strike. At least with ropes that stretch, the roof may get skewed, but at least it won't wind up in the next county and you'll still have SOMETHING keeping the rain out until proper repairs can be made.

In FL the biggest damage in my area came from Hurricane Frances, which caused extreme water damage to homes whose roofs had been damaged by Charley and not repaired yet.