Need help with raising height of my garage ceiling Ask Rick

Need help with raising height of my garage ceiling

This original question was asked on 4-17-2011 by Fish-man and is now posted by Ask Rick. Not sure if I can attach a diagram I made, but was wondering if I can raise the ceiling of my garage (its 9’6″ from the concrete) so I may put in a 4 post lift. What I’m thinking is to put sisters up along the slope of the roof and then put collar ties across. I’d only need to take out 3 or 4 of the truss bottoms, since they are on 2′ centers. I’ve read your other garage ceiling answers and didn’t see the point of leaving the ceiling flat on the outer ends.

Chad, thanks for emailing me the diagrams. I will try to help you will this. As you know I have been asked similar questions on several other occasions, and I want you to realize that I highly recommend you check with your local building and zoning departments before you begin any project like this.Being in the business for over 40 years, one thing I know is that the building departments usually frown on truss modifications unless they have an engineer either do the drawing and calculation or at least approve the drawings. I always had an engineer do this for our company even if I knew I could do the same thing.

Any drawings I give are for your use only and other drawings may be needed to present to the building department.

First of all, after looking and your sketches, I would suggest for better support, that you design the ceiling in a scissor truss form. This gives much more support for the roof, even though it lessons the opening width some. Below is a copy of your sketch of the final product, followed by my drawing.

In your drawing, the concept is to open the entire area up across the span and have your ceiling at the desired height. The main issue I have with this is the span may be too wide for proper support. I would opt for a plan that would lesson the width of the center of the ceiling to 8′ while still maintaining an open ceiling. To do this we would need to modify the construction to include scissors type trusses on each side. Please look at my drawing below.

With this we incorporating several things to help with the strength. They are as follows.

1. A double 2 x 6 header to span the distance at the point where you desire the ceiling height to be. This header may also be microlam if you want.

2. The old truss section above would be modified to form a new supportive truss section.

3. 3′ wide plywood gusset plates would be installed on each side of the upper truss section as indicated by the grey area.

4. Scissors type trusses would be stick built on each side of the lower roof framing section. These would be spaced 8′ apart as shown in the drawing. You could make the spacing 10′ maximum, but this may make it more difficult for you to construct the scissors trusses. These would then be attached to the underside of the header with a top 2 x 4 plate which is part of the truss.

5. An 8′ long 2 x 4 plate would be installed to fit tightly between the two scissor trusses and nailed or screwed to the underside of the header. This will lock the two trusses in place and insure rigidity of the roof as well as proper support.

6. Below each truss section the a triple 2 x 4 should be installed as support. This would go from a double 2 x 4 plate,one of these plates would be the bottom section of the truss and the other would be the on top of the wall, that would be installed under the trusses to the top of the existing foundation block plate or concrete floor, depending on the type of foundation construction you have. See drawing below.

This might be a little more work then you expected, but in the long run it would be well worth the effort because you would end up with a very secure structure and only have to sacrifice some ceiling space.

Rick Maselli is Founder and Editor of Showroom411.com and Ask Rick

Modification To This Question on 4-23-2011

Chad, here is some additional information for you concerning your project. I have also sent you an email with a drawing attached to compliment the explanation. I will include the drawing here as well.

I just wanted to add something in case you had not thought of it. It is highly recommended that you build two temporary walls across 6 of your existing trusses with the four trussed you are going to modify in the center of this span. Remove the drywall from this area to open up the access to these trusses so you can work on them. Then, do the modification to one truss at a time. The temporary walls will go from the bottom of the trusses to the concrete garage floor and will consist of 2 x 4 construction with the studs 16 O.C. You can screw the studs together so that they can be taken apart easily and reused. See drawing below.

This is very important to provide you with temporary roof and ceiling support while making the modifications. After the modifications are complete, remove the walls and drywall all areas where needed including of course the new truss modification area.

Again, thanks for using Showroom411.com and Ask Rick Rick Maselli The Showroom Team


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