Materials

Trusses In Corrosive Environments

Question: 

I am a building designer on a salt storage building project. I would like to use metal plate connected wood trusses in the design. What should I specify for the metal connector plates?

Lumber Species

Question: 

What type of wood is usually used for wood trusses? I live in Louisiana and I would guess pine, but I want to make sure.

Fire Damaged Trusses

Question: 

I have been hired by an insurance company to determine the extent of damage to roof trusses exposed to fire. How much fire damage compromises the structural integrity of the truss?

Lumber Concerns In High Temperature Low Humidity Climates

Question: 

I have been told that the high temperatures and low humidity present in attics can cause deterioration of wood, leading to truss failure. Is this true? If so, what length of time are we looking at and can we see the deterioration in the wood by visual inspection?

Fire Rating For Sloped Roof Truss Assemblies

Question: 

A question has come up concerning sloped roof trusses and fire assembly ratings. Some are reluctant to rely on test results from flat (parallel chord) trusses applied to sloped roof trusses. Do you have any information regarding the suitability of the fire rated ceiling assemblies for sloped roof trusses? Does the “minimum depth” requirement of the parallel chord assembly apply to the minimum depth of a sloped roof truss (i.e., heel height?)

Sprinklers Above Gypboard Ceiling

Question: 

I have a 29 x 72 mobile office with a 2-foot deep wooden truss above the ceiling that a client is required to sprinkler. Is there any way to avoid sprinklering above the gypboard ceiling?

Truss Design Factors Of Safety

Question: 

I am currently working on a project where a wood truss system was loaded with a heavy spring snow. I do not believe the load was beyond the truss's design capacity, but how do you know? Is there safety built into wood trusses? If the trusses were loaded beyond their design capacity, it would not have been for a long duration.

Wood Three Hour Fire Assembly

Question: 

Is it possible to construct an assembly for ceiling between first and second floors using 2x with few layers of gypsum to obtain a 3-hour fire rating?

Lumber Substitution

Question: 

If the truss design drawing specifies using 2x4 1650F SPF, can 2x4 No. 2 southern pine be used instead? What are some things that need to be checked?

Mold On Lumber

Question: 

I am looking for some information regarding black surface mold on lumber. Does it alter the integrity of the lumber stress values? I have a client who wants to use “all dry” lumber for his construction but I do not know if this is really necessary.