Tag Archives: lumber species

Perfect Pitch, Added Expense, and Endwall Roof Leak!

DEAR POLE BARN GURU: Could you tell me the pitch of the roof…for small pole barn…..front wall is 10 foot high…back wall is 8 foot high…rafter span is 13 feet. HERBERT in HAMPTON

DEAR HERBERT: Roof slopes are expressed as the number of inches of rise per 12 inches of run. 24 inches of rise in 13 feet of run would be a slope of 1.846/12 or 8.745 degrees. Some cautions – if you intend to use steel roofing, chances are excellent the paint warranty will be voided due to a roof slope of under 3/12. The side laps of each panel should also have strip mastic placed on top of the under laps to assist in preventing leaks. This slope is also too flat for shingles, unless special considerations have been made for underlayments (most Building Departments require 90# felt paper or an equivalent). I’d recommend you increase the roof slope to 3/12 or greater.

 

DEAR POLE BARN GURU: Can I order specific species with my kit? I’d prefer Doug fir for all the wood, including PT.

Can I choose heavier gauge steel panel for roofing and siding than 29 gauge?

Thanks. JEFF in GREENVILLE

changeDEAR JEFF: You can specify a specific species, however be prepared to pay a premium for doing so, especially in the case of the pressure treated wood. Douglas Fir does not take pressure treating well, so only a few limited chemical formulations are available which will work with it – some of which happen to be highly corrosive to steel. This results in having to place a barrier between the treated lumber and the steel siding, as well as the use of heavily galvanized or stainless steel fasteners.

Most roof truss manufacturers will not guarantee a specific species of lumber will be used in their trusses – so this could become problematic, in your case.

Please read more about lumber species choices here: https://www.hansenpolebuildings.com/2012/03/lumber-species/ (please note this article was written prior to the design values for Southern Pine being reduced).

You may also choose heavier gauge steel panels, however you should read this article first: https://www.hansenpolebuildings.com/2012/01/steel-thickness/

 

DEAR POLE BARN GURU: We built a 30 x50 pole barn with 2 10 ft attached sheds about 1 1/2 years ago. It has sprayed foam insulation and finished inside with sheet-rock. Our problem is every time it rains hard it leaks at the corners on one end. Any suggestions of what we could do to try and find the leak? Thank you so very much for any information you could give us. MARK in SASAKWA

DEAR MARK: I am going to take a WAG (Wild Arse Guess) here. The guess is actually probably not overly wild, since you are telling me the leaks only occur at one end of the building and happen on both sides of the roof.

Your building is 50 feet in length, which means it took 16-2/3 sheets of three foot wide roof steel to cover each side of the roof. This is with the assumption your building has no endwall overhangs. This also means the last sheet of roof steel on one end had to be ripped lengthwise to remove the extra foot of steel. When the rake trim was then installed, there was not a high rib of steel under the trim. When it rains (or snow falls on the roof and melts) water seeps under the edge of the rake trim and into your building. If indeed this is the case, the rake trims on the offending end can be unscrewed, and strip mastic can be used between the edge of the rake trim and the roof steel to keep the water from going where it is not intended to be – screw the rake trim back into place and all should be good once again!

Let me know if this is not the case and we can look for other solutions.

 

Grade Stamps

Walk into your local lumber dealer – whether a big box store (aka The Home Depot® or Lowe’s®), a national lumber dealer (think ProBuild®, Stock Building Supply®, or 84 Lumber®) or the local mom and pop lumber seller and pickup any piece of dimensional lumber.

grade-stampOn it will be a grade stamp – which is a voluntary standard of marking each piece of lumber to assist the consumer in identifying the moisture content, product grade, species or species grouping, the accredited agency under who’s authority the lumber was graded, as well as a unique mill number identifier or the name of the sawmill which produced the lumber.

One of my son Brent’s first days of working with me involved placing Simpson Strong-Tie® joist hangers on rafters. The rafters were different colored wood – Brent noticed the difference between the darker, more reddish hue of the Douglas Fir rafters as opposed to the whiter color of the ones which were HemFir. I explained to him what the information on the lumber grade stamps was, including the indication of the species of lumber.

The “big giant head” for lumber grading starts with the ALSC (American Lumber Standard Committee, Inc. www.alsc.org).

The ALSC, is a non-profit organization comprised of manufacturers, distributors, users, and consumers of lumber. It serves as the standing committee for the American Softwood Lumber Standard (Voluntary Product Standard 20) and in accordance with PS 20, administers an accreditation program for the grade marking of lumber produced under the system.  This system, the American Lumber Standard (ALS) system, is an integral part of the lumber industry’s economy and is the basis for the sale and purchase of virtually all softwood lumber traded in North America.  The ALS system also provides the basis for acceptance of lumber and design values for lumber by the building codes throughout the United States.

As noted above, a function of the ALSC is to maintain the American Softwood Lumber Standard.  The ALSC in accordance with the Procedures for the Development of Voluntary Product Standards of the U.S. Department of Commerce and through a consensus process establishes sizes, green/dry relationships, inspection provisions, grade marking requirements and the policies and enforcement regulations for the accreditation program.  The ALS system as a whole is set up to give manufacturers, distributors, users and consumers a mechanism to formulate and implement the Standard under which softwood lumber is produced and specified.  Participation of each segment of the industry is an integral part of the program and provides the industry with a direct voice in the standardization and accreditation program as it evolves into the twenty-first century.

In the case of Brent’s rafters, the Douglas Fir ones were marked with the WWP® logo of the Western Wood Products Association (www.wwpa.org) which is the largest association of lumber manufacturers in the United States. The Douglas Fir ones were marked with a mill number to indicate the producer, however the others were produced by Idaho Timber (www.IdahoTimber.com).

The rafters happened to be graded as Select Structural (SelStr), which indicates a relatively smaller group of allowable defects than the more commonly seen framing material, which is normally graded as #2.

For a brief overview of allowable defects in lumber, please read more at: https://www.hansenpolebuildings.com/blog/2013/12/lumber-defects/

The species of lumber was how Brent and I originally got into the discussion of grade stamps. It was indicated by the DFir and HemFir designations on the rafters.

All of the framing lumber used on this building (as well as all Hansen Pole Buildings) is seasoned to a moisture content of no greater than 19% at time of surfacing, which was indicated by the “KD” on the grade stamps.

Lots of information contained in a little stamp – but as Brent’s older sister Allison says, “My Dad knows more worthless trivia than anyone”.