Field Repairs & Alterations

Determining The Load Capacity Of Trusses

Question:

I am doing research for clients who have flat roof trusses to which they are adding a second story. We are now looking for information on the trusses to determine what their load capability is. What do you need to know to help us determine this?

Bottom Chord Dead Load

Question:

I have built a 30 ft. x 40 ft. pole barn with nine 30 ft. 2x4 7/12 pitch trusses that are 5 ft. O.C. I am planning to finish out the interior and will attach 7/16 x 4 x 8 OSB sheets to the trusses for my ceiling. Along with this, I will have to add several 2x4 nailers across the 30 ft. span between the trusses to attach the sheeting to. My question is: will these trusses have any problem supporting this ceiling? I am not planning on anything being placed in the section above the ceiling and there will be no walls or supports erected between the ceiling and the floor.

Wind Loads From Solar Panels

Question:

I am looking for information on point loading trusses. We manufacture mounting structures for solar panels. Typically, 10 to 15 sq. ft. of solar panel is supported by one standoff. Under extreme conditions – 50 lbs. per sq. ft. of wind load - we can transfer 500 to 750 lbs. of force onto one point of one truss. Are there any standards on this issue?

Damaged Trusses

Question:

I have just moved into a new home and during the construction I noticed that one of the trusses in the garage was damaged. The web plate had come off in two different locations. I notified the builder and they said they would take care of it. Approximately two weeks after I moved in, I noticed the ceiling in the garage started to sag, so I went into the space above the garage and found the truss was never repaired. I again notified the builder and they sent someone to fix it. I went and looked at the fix and this is where my question comes in.

Vent Sizes

Question:

I have mono trusses on either side of a firewall. I have the fire rating/wall material between them. Can I place a ridge vent above these two? Or should I use vents? How do I calculate the appropriate vent sizes and styles?

Adding Tile To Existing Floor Trusses

Question:

We are planning to add 1/2 in. cement board and 3/8 in. quarry tile to a kitchen floor. We need to know if the floor trusses will handle the additional weight. The floor trusses are 19.2 in. O.C. and the loading numbers are 40-10-0-5. What do these numbers mean?

Truss Repairability

Question:

Occasionally we deal with truss failures due to impact and or crushing forces such as trees falling onto roof structures. At what point can the truss no longer be repaired? Also, what should an adjuster look for when determining repair-ability? Or should a storm adjuster basically punt and call a consultant for every truss failure?

Truss Failure And Repair

Question:

I am a professional engineer looking for information concerning the failure of metal plate connected wood trusses and methods of repair. I am looking for this information with regard to developing recommendations for the repair of truss systems in the floor structures of two-story multi-family dwellings. I see frequent failure of truss systems of this type in both in bending and due to catastrophic failure at the gussets.

Decking On Bottom Chord

Question:

Can I put a wood deck (1/2 in. plywood) on top of the bottom chord of a 26 foot span truss 24 inches on center?

Charring Of Trusses

Question:

Our home caught fire last month and burned partly through a tongue and groove ceiling to the trusses. Some are charred. Our contractor did a moisture meter test. An engineer for the insurance company said the trusses were only smoke damaged & the moisture meter test is invalid (it can be set to read anything). I found one article on charred trusses, but it’s pretty vague. We do not feel safe with the insurance engineer’s assessment because some of the trusses are obviously charred. We hired an engineer who agreed with us.