I've installed a four post lift in my garage and it works great. I can lift my old Chevy to the max and have about 58" underneath the ramps. Pretty good considering I've got a 10'3" ceiling.

I've considering altering two trusses that run parallel with the length of the four post lift. I took a peak in the attic and see that I could alter trusses #3 and #4 from the exterior wall. The entire roof line uses 19 on the same truss (my single garage is on the exterior while the remaining are over rooms, laundry, hallway, bathroom, etc). While up in attic, I came across a sticker on the truss from the manufacturer which shows the loading (TCDL, TCLL, BCDL and total load). I reached out the truss manufacturer who said I need to find the engineer of record (12 year old home) and have them determine how the truss can be altered. Then they framing company would build a truss to order.

I have a Fink style truss and would like to convert to a coffer style truss. In my picture, you can see notched out rectangular red box. I'd like to get eight to ten feet long and at least 12" high (18" would be great!).

Anyway, any experience in working with a structural engineer to approve a truss design? I only need to alter two of the identical 19 trusses, which are 24" on center. The truss manufacturer suggested two trusses wouldn't cost too much, but I'm afraid the engineering costs would make it cost prohibitive.

The picture you posted didn’t come through on my iPad so I’m shooting in the dark to some extent.

I see you’re in CA so my comments probably aren’t relate to as far as cost. When we’ve needed to modify a few trusses our engineer typically charged us about $500 for a stamped drawing. This is someone that we’ve done business for years so I’m sure my price would be lower than yours.

In very general terms we had to gusset both sides of the 2x4’s with 3/4 plywood over a specified area installing the new 2x’s. After installing everything and following the specified nailing pattern then we could cut out the portion that we needed to.

Of course this is specific to each re-design and should not be a general rule.

If you don't have a stamped professional engineer drawing, and bad stuff happens, it is really bad.

You also have assumed liability for future owners. Their home inspection will find the modifications, note it, and without PE plans, it would not be good.

quote:

Originally posted by smlsig:
In very general terms we had to gusset both sides of the 2x4’s with 3/4 plywood over a specified area installing the new 2x’s. After installing everything and following the specified nailing pattern then we could cut out the portion that we needed to.

Of course this is specific to each re-design and should not be a general rule.

That's what we generally do but on subfloor where trades have drilled/notched floor trusses. We try to use 2x6's instead of 2x4's but it falls on what the truss design company tells us to do.

quote:

Originally posted by 4MUL8R:
If you don't have a stamped professional engineer drawing, and bad stuff happens, it is really bad.

You also have assumed liability for future owners. Their home inspection will find the modifications, note it, and without PE plans, it would not be good.

This is the best course of action. They're the professionals and they will figure out the truss engineering for it. Will cost some money but well worth it, IMO.

As always “it depends”.

Some people live where permits, drawings and even plans are not needed to build. I tend to overbuild everything.

In a “no code” situation -

“Sistering” is attaching a new piece of lumber along side an existing piece to strengthen the existing one. If you were to be in a rural situation where building codes were lax, you might sister new lumber, in essence installing rafters to strengthen existing trusses. As far as overbuilding, I would be tempted to use say 2x10’s on both sides of a 2x8 truss (three thicknesses total) and glue and screw it all together. Even more lumber might tie the new rafters to trusses on either side, gaining strength from one another. Once all that is done you could probably cut out what you want from the few trusses that are in the way.

I have noted before - When advice is given it is assumed you are standing beside the donor, live in his community and have to follow local regulations. Building in some places, say rural Alaska, you can do pretty well as you please.

Would I build/repair as I have suggested? I can picture right now a garage poorly built 100 years ago that is sagging everywhere. That could be repaired with sistering much of the roof and no one would blink an eye about it.

^^^

Yeah but he’s in California. I would bet my Porsche that he has to have engineered stamp drawings to legally make any modifications.

I just found the engineer of record, which in this case is actually an architect. The company no longer exists but this guy is with a new firm. I'll reach out to him.

The City building department wants me to pull a permit and the framing company won't build a new truss unless the engineer has done the analysis.

I'll follow through the process far enough to get a dollar figure, but until I need the space (second project car or my 911), I don't need the maximize the ceiling space just yet.

Engineer to re-engineer the truss - $1000
Permits - $500
Truss - $500-800
Blood, sweat, tears and cursing - $1000

It's a fun exercise.

Russ, glad you found him. However, if the original engineer (architect) can’t (due to workload, or in some cases age or even death) or won’t recheck it for you (many don’t keep records for much more than the statute of limitations in the jurisdiction), most jurisdictions will allow you to hire another structural engineer to look at the work, do the measurements needed to model it, and then analyze it for the required loads in the new configuration. I’m a structural engineer and have done this on the steel side a number of times for trusses, open web steel joists, and other members. That said, I’m not licensed in California so the rules there could be different.