The Stovebolt Site Forums The Shop Area The Tool Chest PreFab Truss Shop Mod's

Quick background - My shop has 10 ft 6 in clgs and I need 12 ft for a 4 post lift. My trusses are on 5 ft centers, so I only need to modify 1 to get a lift in. I was chatting with the lift salesman at the Mecum auction yesterday, and he had some photos of shops that have done similar mods, with great success. Now before some of you guys say something like "did you know that the trusses are integral to holding the roof up, and if you mess with them it will fall on you and kill you" not to worry, safety is highest priority!

Now the actual question - Do any of you guys have first hand knowledge of doing a similar mod (taking the middle out of a truss, and reconfiguring truss to maintain load)?

I have done hundreds of buildings over the past 43 years. Your best option would be, instead of cutting a truss, to move it over and modify the roof decking. Is it plywood and shingles or 2x4s and steel roofing?

Allen--
As a former Building Official (now retired) I provide this for your consideration:
--wood trusses are properly called 'Engineered Wood Trusses' for good reason--their were designed by Engineer for their particular span, loading and configuration.
--Any proposed modifications to engineered trusses should be re-Engineered before proceeding
--Suppliers who manufacture and sell wood trusses generally design them on computer, then a registered Engineer signs off on that design.
--I have run into numerous cases of trusses which have failed, or were about to fail due to Un-Engineered modifications
--I have also seen several cases of failed 'farmer' trusses where folks 'designed' their own trusses and they collapsed the first winter
--Many wood trusses may look simple but there are a lot of loads and loading to take into consideration in their design

My suggestion to you is to contact the truss manufacturer (generally stamped or marked on each of your trusses) or perhaps the structure was built for you & you know who that manufacturer is. Then explain your planned modification and see what they can come up with.
I am thinking you perhaps could have a new Engineered wood truss made which would 'sister' to the existing truss which could then be removed.
From my experience, truss manufactures are good to deal with to solve problems such as yours
Good luck Delky dave in WYO

The trusses I modified in 1983 to accommodate a higher ceiling when I turned a Grade B milk barn into a 3-bedroom house haven't failed yet. The first winter after that project was finished, we had 5 inches of solid ice on the roof after a 36-hour sleet storm. However, I tend to over-build everything from race cars to houses. The original trusses were built from rough-cut oak from a sawmill down the road in the early 1950's. That milk barn went from a 16 X 32 foot concrete block building with a tin roof to a 3,000 square foot 2-story structure after two remodel jobs. The original building is still there- - - -enclosed on all sides by the modifications.
Jerry

Thanks Guys.

Panel, that's a little more that I've bargained for. It's a Steel building with 2X's for trusses.

Delky, I've attached the photo I got from the lift rep. I'm thinking he may have had a truss co come in and double up and press on those prefab nailers. I understand those have to be applied with a 10K psi press. Folks think they can hammer them on....no way. I'll see if I can get one to come take a look. We don't have a problem with snow here, but hurricanes can surely ruin your day.

Jerry, I too have an overbuilding problem. I just hate to do stuff twice.




[img]https://photos.google.com/photo/AF1QipNvNPZBzdSZ_YswhCTATuVfUQauLdj_YzHJJuMc[/img]



Truss Mods

Looks like this requires a Google login before it can be viewed.

I'll see if I can post the pic itself. Does the second one require login as well?

Yes.

Retrying the pic post...

Allen
I stand by all my comments above. I am sure it is possible to achieve the mods to your trusses-----get professional help!
Good luck! Would like to know how it turns out.
delky dave in Wyo

I'm not an engineer, but I have built many structures and made my own trusses for several of them. In order to gain height for two of the observatories I built I made scissor trusses. Easy to make, and should be able to modify an existing truss. Essentially rather than having a 2 x 4 running from wall to wall (to prevent walls from spreading under load and letting the rafters fall) a 2 x 4 is run from the top of each wall (attached to the bottom of the rafter) to about 2/3 of the way up the other rafter. Where the two cross they are bolted together (with a spacer the thickness of the rafter). This makes a nice solid set of triangles, which gives the set up structural rigidity. If you look up scissors truss on google you can see what I mean. It wouldn't involve removing the existing truss, just removing part of the center of the existing truss AFTER the scissors are in.

I'll see if I can upload a drawing.

Tim

Another solution. A coffered style ceiling. Can not get anyone to come out for 1 or 2 trusses.

Are your existing trusses running front to back or side to side in relation to the line of the lift bay?

Mike B

Front to back, and only need to modify one truss. They are on 5' centers. The pic is of engineered pre-fab trusses. Note how small the corner brace on the former lower joist is. That tells me that the force has been effectively moved to that upper corner, where you find the very large plate and intersection of 4 joints.