Performance

Post Fire Retardant Treatment

Question: 

Is a Class A fire rating (provided by our liquid spray-on fire retardant) acceptable in certain situations?

Installing Valley Sets

Question: 

What are the requirements for installing “valley set” overlay roof trusses? I am interested in nailing and support conditions. Some engineers ask for the bottom chord of the valley truss to be ripped to match the roof pitch of the underlying trusses. Is this necessary?

Roof Truss Nailing With Hurricane Clips

Question: 

If you use hurricane clips to secure roof trusses from uplift, are you allowed to use fewer than the typical three nails in the bearing heel of the roof truss? I am concerned because we want to do the right fastening schedule, but three nails in addition to the hurricane clip splits the wood. What is the standard recommendation?

One Hour Fire Rated Assemblies

Question: 

The Gypsum Association “Fire Resistance Design Manual” (GA-600-12) lists file RC2601 with two layers of 5/8 in. gypsum wallboard (GWB) on wood joists.

Installation Guidelines

Question: 

Are there any associations that have recommendations for the installation of wood trusses?

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.

Impact Sound Transmission Through Floor Assembly

Question: 

A condominium project I am involved with is experiencing a sound transfer problem through the floor/ceiling assembly between the first and second floor. You can hear every footstep, from an adult to a child. The floor assembly consists of a carpet and pad, 3/4 in. OSB sub-flooring, 15 in. deep wood trusses at 16 in. on center, 9 in. fiberglass batt insulation and a 5/8 in. gypsum board ceiling. The trusses span 20 ft. with air/heat ducts between the trusses. Will an additional layer of 5/8 in. gypsum board attached to 7/8 in.

Attachment Of Scissors Trusses

Question: 

What is the correct method of attaching scissors trusses to the top plate? I read recently in a trade magazine that this type of truss should be toe-nailed on one end and attached with slotted clips on the other end. According to the article, this is to allow for movement of the truss. We require PE stamped spec sheets from the truss manufacturer to verify trusses meet wind and snow loads. These sheets give bracing requirements but never give recommended attachment requirements.

Bracing Schematics

Question: 

Are there any schematics available on how to horizontally brace a 7/12 pitch roof?

Snow Load

Question: 

I am a truss manufacturer in an area of the country that often has some pretty severe winters. It concerns me how little some of the local builders seem to know about snow load design. What are some of the things that need to be considered?