What wood grade used in Cape Cod, MA in 1955?

[structuresguy]

I am working on an evaluation and renovation of a wood framed hotel in Cape Cod, Massachusets that was built in 1955. It has prefab wood trusses (like metal plate, but with plywood plates), 2x12 floor framing, and 2x4/2x6 walls with plywood sheathing. The owner sent me lots of pictures showing the trusses, roof sheathing, floor framing, wall studs and sheathing, etc... In none of the pictures can I see any grade stamps. I don't know if it was common place to stamp lumber back then. I am going up there later this week to inspect it in person, but I would like to get a feel for what to expect before I arrive.

Does anyone know what was the common type and grade of wood dimensional lumber used back in 1955 in Cape Cod?

Thanks

 

[MiketheEngineer]

Probaly some kind of Fir grown regionally or in Canada

 

[structuresguy]

Thanks Mike. Anyone else agree (or disagree) with Mike? Right now, the type and grade is critical to me. I am very borderline on making the existing construction work. I went up there, but could not find any grade stamps on anything.

 

[SteelPE]

I had a similar situation to yours not to long ago. The building was built in the 1960’s and the grading information on the side was a little different to what is used today. I ended up calling one of the local grading agencies who offered to come down and graded the building for a fee. They also gave me a copy of what their specs are today. We ended up not needing the information as the floor system worked for the final loads.

Just one other thing you can do if you are not comfortable with what is out in the field.

FYI this particular building was in Massachusetts and built using WCH (west coast hemlock). Therefore in the 60’s the wood could have come from anywhere (not necessarily Canada). I’m not sure if the same holds true for the 50’s

Sorry I have no other information for you.

 

[SLTA]

I'd take a sample and have it tested.

 

[BAretired]

If the material came from Canada, it could have been Douglas Fir or S.P.F. (Spruce/Pine/Fir). A 2x4 would have been 1 5/8 x 3 5/8, slightly larger than the current 1 1/2 x 5 1/4 although it could have shrunk a bit after all these years. It could have been Select Structural, No. 1, 2 or 3. The most likely is No. 2.

In those days, D. Fir was considered stronger than S.P.F. but that has changed in recent years. It should not be too hard to distinguish D. Fir from S.P.F. if you have an opportunity to inspect the material. Fir is a much denser material.

BA

 

[structuresguy]

Thanks guy. Unfortunately, I couldn't tell the difference between doug fir and pine if I was standing 6 feet from each tree, and I had a picture book showing me what they look like. Wood is not really my thing.

I attached a picture. Not much to go on, but maybe someone can tell from it.

Thanks.

 

[structuresguy]

I will look into getting the wood tested. I found some wood capacity tables from 1957. So assuming that these applied in 1955, and if it is equivalent to doug fir SS or maybe #1, then I am ok. If not, well, then I don't know. I would have to beef it up in areas that we are modifying, but not sure if the local authority will make me improve the entire structure. I sure hope not. We are a level 2 renovation, according to Mass building code, so as long as I can show that it worked by the code when it was designed, I should be ok.

 

[BAretired]

Looks like fir to me. Don't know about the grade. I would not assume SS or No. 1, but No. 2 should be pretty safe. By all means, get the wood tested. Then you will have a proper basis to check the design.

BA

 

[SteelPE]

What are you trying to do to this structure? Are you increasing the load on these roof trusses?

 

[structuresguy]

Not really increasing the load, but we are "changing" the bearing point of the trusses. Currently, the trusses are 28 feet long. They bear on 2x6 wall at one end (zero overhang basically) and at the other end, the bearing point is in question. there is a 2x6 wall about 6 feet from the other end. The trusses bear on this wall. But there also is a row of posts out at the tip, with a very shallow beam across the posts (don't know if it is even a 2x4 deep, as it is still all covered by finishes). So given the shallow depth of the beam, we are not sure if it is carrying the load, or was ever intended to carry the load. It gets more complicated in that the trusses don't have a web arrangement that you would expect to bear on the wall 6 feet in from the end. They are fabricated as is they were intended to bear at the ends.

so, we are removing the wall 6 feet from the ends, removing the posts, and replacing the posts with a new 2x load bearing wall. so now the trusses will be forces to bear at each end. Given what I know of them, and the loading by today's code, I can just get them to work for gravity loads if i assume #1 or SS doug fir. Anything less, and its no good.

Of course, the tension members are only 1x8's, so they fail in wind uplift (120 mph zone). So I am already going to have to beef them up as it is. But as usual, cost is a major factor, so I don't want to do anything unneccessarily. I know the owner will have a fit when I tell him to get the wood tested. He didn't even want to get a geotech report for the new foundations. I had to show him in the existing building code where it said it was required BY CODE, not just by the good recommendation of his hired design professional!

Thanks for your help.

 

[SteelPE]

Sounds like you are in a tough situation there. Just keep in mind that the latest revision to Chapter 34 of 780CMR is dated 2/5/10.

You might want to call the NELMA, they may be able to help you solve your problem.