Tag Archives: structural engineering

Garage Idea, Barn Doors, and Another Eave Height Question

Today’s blog discusses a Garage Idea, Barn Doors, and Another Eave Height Question.

DEAR POLE BARN GURU: 30’ wide x32’ deep garage 6×6 posts spaced 10’ apart except one side 16’ span. 2×8 headers doubled 2×6 side walls supporters on slab. 2×6 rafters with on 2’ centers with 2×6 connectors between rafters also on 2’ centers 1’ fall to read. Metal roof & sides. Does this sound thanks. JIM in PORT O’CONNOR

DEAR JIM: My expert opinion is you are setting yourself up for a failure – hopefully one which will not injury anyone in the collapse.

The right thing to do is to contact a post frame building kit package supplier who can provide you with not only the materials, but also the engineer sealed plans specific to your structure.

 

DEAR POLE BARN GURU: Can I order just steel door barn doors and tack systems from you versus an entire building? And how would I do that? And for a split door system to accommodate an opening of 10ftX5ft, what would be a rough cost estimate. Thank you. ROCKNE in PLACERVILLE

DEAR ROCKNE: Due to issues with damage in shipping, we only supply doors with the investment into a complete post frame building kit package. We suggest you visit the Pro Desk at your local The Home Depot as they should be able to assist you.

 

DEAR POLE BARN GURU: Is the “height” considered the peak or total height? If so, what are the exterior wall heights on an 8′ high building (for example)? Thanks in advance for your time. SHAWN

 

 

 

DEAR SHAWN: Post frame buildings heights are “eave” heights. Here is some reading on eave height: https://www.hansenpolebuildings.com/2015/02/eave-height-2/. An eight foot high building has an eave height of eight feet from the bottom of the pressure preservative treated splash plank to the underside of the roofing at the outside of a sidewall column.

 

 

 

 

 

Structural Engineering for $400

I’ll take Structural Engineering for $400 Alex

Proper Engineering in post frame construction can not be overlooked.

Alex Trebek has hosted Jeopardy!, the iconic daily syndicated game show, since 1984. With over 7,000 episodes aired, Jeopardy! has won a record 33 Daytime Emmy Awards. Some of you may even have tuned in for an episode or three.

Today’s Answer Is:

Insufficient Data to Provide an Answer

And reader PAUL from FINKSBURG has the question:

“What size header would be required for a 20′ wide overhead garage door placed on the truss bearing wall?”

Okay, enough of my being snarky. The answer to Paul’s question should be clearly indicated on the engineer sealed plans for his building, along with the required connections from truss to header and header to columns.

If somehow the engineer of record overlooked this critical element, he or she should be contacted immediately to provide the missing data. Even worse – maybe an engineer happened to not design the building, in which case CALL ONE NOW.

Whilst this may appear, on the surface to be a simple question, there are a plethora of factors which go into the determination of a structural header to carry roof loads. This would include, but are not limited to:

Pg – the Ground Snow Load

Ce – the Snow Exposure Factor (sites which are open to the wind allow snow to blow off the roof, sites which are protected from the wind keep snow on the roof)

Is – the Snow Load Importance Factor (Risk Category I buildings are a lower hazard to human life, therefore the flat-roof snow load will be reduced)

Ct – the Thermal Factor (heated buildings melt snow off, unheated buildings allow snow to build up)

Pg, Ce, Is and Ct are multiplied together along with 0.7 to determine the Flat-Roof Snow Load (Pf)

But wait, there is more…..

Pf might be further reduced depending upon the roofing material (steel roofing being slick allows snow to slide off quicker), whether or not snow retention systems are present (which hold snow on the roof), as well as the roof slope. Mix them all together and the Sloped Roof Snow Load (Ps) is created.

The dead loads imposed upon the roof also need to be added to the mix – the weights of trusses or rafters, purlins, roof sheathing, insulation supported by the roof system, roofing, truss bracing, ceilings are amongst some of the weighty culprits.

Once all of these contributing factors are combined into a psf (pounds-per-square foot) load, concentrated loads are applied to each of the truss bearing locations along the header – these are based upon ½ of the truss span (including any sidewall overhangs) multiplied by the truss spacing and the applied loads.

Not only does the header need to be verified for adequacy in load carrying capacity, but also limited in deflection. A sagging header can cause unsightly rooflines as well as preventing doors from operating correctly.

Self-engineering is not a good choice – call your engineer….now!