heavy timber truss preferable species 1

[Robert216]

This might be more of an "aesthetics" question. Anyway, I've designed a few heavy timber trusses. The species of truss members are currently #1 SYP. Structurally, everthing is fine. I am now beginning to wonder if this species is the most suitable for strength AND aesthetics. It seems like most info on the web is driven by a marketing agenda of lumber companies. Is there a recommended species for HT members. I am worried about "straightness" of the member as well as long term warping issues that may be possible. It's not very often that I get to "play architect" but this time the architect left everything up to me. He just wants it to look good. Thanks in advance for any recommendations or information. Rob

 

[HouseBoy]

I see douglas fir most commonly for heavy timber truss material. (I'm in Cincinnati and I am told the lumber comes from a distributer in Louisville.)

 

[Robert216]

Thanks houseguy.

 

[RARWOOD]

The two most common species of wood used in trusses with solid sawn timbers (5x5 and larger)or glulam members, are Douglas Fir and Southern Pine. Douglas Fir is more stable than Southern Pine, so from the stand point of straightness Douglas Fir is the better choice.

 

[MiketheEngineer]

Agree w/ RARMBJ - but SYP is usually a bit stronger grade for grade.

 

[HouseBoy]

My experience is that SYP is not as available in the larger sizes and Doug Fir is more attractive (including with stains).

 

[MiketheEngineer]

Agree w/ houseguy

 

[SperlingPE]

The last timber truss that I did was spec'd/designed douglas fir. Supplier suggested Alaskan Cedar after speaking with architect.

 

[ThePioneer]

I disagree that douglas fir is more stable than Southern Pine.

Glued laminated timber will most often be less costly than large solid timbers. And they will not shrink and twist like large solid timbers.

 

[ctcray]

We design and build using either Select Structural Doug Fir or glulam. The doug fir is green and will check giving a more "rustic" look. The glulam will be straight and have a cleaner finish.

 

[swsengineer]

I engineer and detail with glulam and heavy timber every day. Southern Pine is generally cheaper than doug-fir but it's harder to find in long lengths or large sizes. Customers are generally happier with the doug fir because it tends to be straighter, cleaner, and check less. If cost is an issue and the beams needed aren't too long or large just go with Southern Pine otherwise use Doug-Fir. My day job is being an engineer for a Southern Pine Custom Glulam manufacturer. S.Y.P. Glulam is a great alternative but will usually cost more. The sizes and spans can get to where glulam is the better choice. We convert large solid timber jobs to glulam all the time and usually loose truss jobs that get compared to small solid timber trusses. I would consult with a local heavy timber supplier.