Thru-Bolt (or Cable) question


Old 03-20-07, 06:47 PM
Thread Starter
Join Date: Mar 2007
Location: downeast maine
Posts: 35
Thru-Bolt (or Cable) question

Hi all,

I've been camping out in the electrical forum recently but I now have a question/problem that's probably more suited for this one.

Does anyone know where I would get a thru-bolt or cable that's used to tie the two sides of a house together. I would need one that's about 24 feet long.

The reason I need one is that I have a large vaulted ceiling. I'm afraid the collar ties used to tie the two sides of the roof together are not strong enough (they're every 48 inches and they're located about 1/3 the distance from the ridge to the top plate. As a result, I believe I'm seeing the walls they're sitting on start to bow outwards very slightly. I've thought about different solutions and the thru-bolt or cable seems the most palatable.

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Old 03-21-07, 09:46 PM
Join Date: Aug 2004
Posts: 1,150
You'll also need a jack to lift at the ridge as well.
Old 03-22-07, 07:41 AM
Join Date: Jun 2006
Location: USA
Posts: 110
I would use a string line or laser level on the exterior of the suspect walls to verify that thet are indeed spreading before I started.

Any hardware store, Lowes, Home Depot, can sell you wire cable and cable clamps. If you intend to pull the wandering walls back into line you'll need a come-along. Actually, I'd get several of them (think rentals) and pull the entire stretch of walls evenly. Be prepared to see some drywall cracks if you do this.

Edit: Turnbuckles (large, robust ones) mounted as part of each cable could be used also to reposition the walls. This would make it possible to adjust again in the future.

[The cables and hardware used to construct post-tension concrete slabs might work, but I'm not familiar with them and don't know where you'd get them.]

These cables will likely come to be under a considerable strain over time. I would not use lag-bolt style eye bolts to fasten the cables to the walls. I would run long bolts completely through the framing and walls and use metal plates under the washers on the exterior, to be sure the bolts do not rip out.

I'm not convinced you'll need to jack up the ridge. If you pull the base of each set of rafters back into proper position, that ought to raise the ridge back up where it belongs, if it's sagged.

Just on a side note, and in spite of the fact that you didn't ask whether this was a good idea, I don't think anything would ever tempt me to buy a home on which this unconventional repair had been done. And I would wonder whether it might have implications for your homeowners insurance.

The cables running across the middle of the room are going to look like heck, to say the least. You might be able to somehow dress them up up as 'faux" beams, but I think it will always look strange.

Last edited by aq_guy; 03-23-07 at 07:05 AM.
Old 04-08-09, 11:38 AM
Join Date: Apr 2005
Location: Houston, TX
Posts: 74
Cable pulling walls together

A search found this old posting.
I'm now in the process of trying to do the same basic thing.
It's an old house and the rafters are puling away from the top beam. Hurricane Ike problaby didn't help either.
I want to start over the garage where the top beam sags 2 to 3". The rafters in this area also sag and and have pulled away from the top beam at least 1/4".
I have no illusions about returning the framework to it's original mid 50's condition (if it was correct even then) but want to keep it from getting worse.
My idea is to use maybe two 1/4" cables and turnbuckles and wired through holes (sleeved with 1-1/2" long pipe nipples for strength) near the bottom ends of the rafters.
I can also connect the opposing rafters near the peak with bolted or nailed 2x4's.
Jacking is possible if needed. Rafter bracing down to the joists may be required to cure that sag.
I assume all this should be done before they replace my roof.
Any suggestions or warnings of potential problems?
Old 04-08-09, 02:32 PM
Join Date: Mar 2009
Location: WA
Posts: 1,167
The forces you will be working with could be minor or tremendous. I would hire a Stuctural Engineer to design an answer for you. I'd hate to hear of someone getting hurt from trying to do it themselves. If you hired a professional Contractor to do the work, he would most likely hire a S.E. also. It's called liability. Then at least your Homeowners Insurance would cover what his didn't. Before you run out and buy some 1/4" cable, at least find out what it's rated for in terms of breaking strength. And wear a hard hat. Be safe, GBR
Old 04-08-09, 03:02 PM
Join Date: Jun 2008
Location: Southeast, Pa
Posts: 358
This is not a do it yourself project. As GBR says, get a professional to do the work and either you or he needs to hire an engineer to do detailed drawings and specs on exactly how to do this. You or others in the area could be killed if something failed.


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