I'm considering removing some walls in the center of a home with Howe Trusses (see pic). I know trusses are normally designed to transfer all the load to the exterior walls, but what concerns me is that the entire length of the house is supported roughly at the center by a wall capable of being load-bearing through to the foundation below. And while I've owned homes with other styles of trusses, these Howe trusses look ideal for a design where the load is split between the center and the outside walls. So I'm not confident I can remove those center walls
The exterior walls measure 25' apart on the inside (~25' 4" on center); I'm in coastal Maryland, so my snow load is 25 or 30 psf. The roof is a 4/12 pitch, and the house was built in the 1970s.
Does anyone know for certain that the trusses in question can handle the full snow load with no center support? I realized most people, including me, would say "ask an engineer", but I suspect someone here has experience with this truss design over this very common span distance and therefore knows the answer.
Best Answer
Trusses are designed based on 1) top and bottom chord size, 2) size of web members, 3) size of connectors at each chord, 4) species of wood, 5) pitch of roof.
I'd go to your local truss manufacturer and give him all the info I listed above and have him run it through his "truss calculator". It'll take him about 5 seconds and you'll know for sure. (Or, go to your local truss manufacturer and ask him to run a printout for 4:12 truss spanning 25'-7" out to out and take the printout home and compare.)
You will be able to compare everything fairly easily, except the connector plates pressed into the chord joints. For that, ask to measure one of their standard steel plates and measure distances between deformations and depth of deformations.