This Monday the Pole Barn Guru answers questions about roof trusses at 4′ o.c., ways to solve condensation issues, and sliding door options.

DEAR POLE BARN GURU: My question is I just purchased some roof trusses that are 32 feet long heel to heel they are constructed with 2 by 4s can I put these on 4 foot centers? Thanks. CRAIG in BELVIDERE

DEAR CRAIG: You can if you want your building to collapse in a moderate snow event. Along with your trusses, you should have received an engineer sealed truss drawing with all specifics as to what can be carried by it and spacing. If you did not, and they are prefabricated metal connector plated wood trusses, there should be a manufacturer’s stamp somewhere on truss bottom chords. You could then contact them and give them truss specifics (and probably a few photos showing lumber grades, web configuration and steel connector plate sizes. From this, they may be able to determine what you have actually spent your hard earned money on.

If you are unable to determine where they came from, another alternative would be to take their information to a Registered Professional Engineer with roof truss experience. For a few hundred dollars, you may be able to get an opinion as to their strength.

DEAR POLE BARN GURU: Hello, I have a 30x46x16 all steel pole barn that I am having condensation problems with. My question is what is the best thing I can install or do to help the problem? I have been told by others to install a ventilation exhaust fan controlled by an thermostat. I do have electricity in barn. I also have a wind turbine I haven’t installed yet too? Should I put both of these items in or one of them? And if so, do you guys install these items? Please help, its rusting all my tools and growing mildew in my RV!! Thanks ALYSSA in LEWIS CENTER

DEAR ALYSSA: You have found a challenge (one of many actually) Quonset steel building providers never seem to mention – condensation (read about other Quonset issues here: https://www.hansenpolebuildings.com/2011/07/quonset-huts/).

The two best things you can do are to seal your concrete floor (https://www.hansenpolebuildings.com/2019/02/how-to-properly-apply-post-frame-concrete-sealant/) and have two or more inches of closed cell spray foam insulation applied to the inside of your steel building shell. An exhaust fan might help, provided it can adequately move enough air (need to move between 3000 and 4000 CFM – cubic feet per minute) and it will require an air inlet of similar dimensions. We are not contractors, so we won’t be able to assist you with any installations.

Figure 27-5

DEAR POLE BARN GURU: Hi. Not really looking for a whole building. What I am looking for is an exterior sliding door to install onto a shop wall. The Shop is a timber frame unit. The opening is roughly 6 feet wide by 7 – 7.5 feet tall. I have not yet taken exact measurements. I will as soon as I can find a vendor within my price range.

I was very intrigued by your video presentation describing the “nail on” round track system. Also, this shop is in an odd location. It is a basement shop under my house, the house is built on a slope, so the wall I want to put the door onto is at ground level, but the opposite wall is fully underground. Since it is an exterior door to my basement any info on weather sealing for the cold Vt. Winters would be greatly appreciated. ANDREW in WESTMINSTER

DEAR ANDREW: Whilst I can appreciate you thinking a sliding “barn style” door might be a solution, I am doubtful as to it truly being a viable design solution. At best a sliding door will be a challenge to insulate beyond a bare minimal R value. A bigger concern is you are not going to achieve a tight air seal.

A design solution I can recommend (although it may stretch your budget) would be to go with an insulated commercial steel double entry door (six feet wide) in steel jambs. These doors will afford a secure access to your shop, are insulated and can seal air tight.

Although we typically only provide doors with our complete third-party engineered post frame building kit packages, you can message Materials@HansenPoleBuildings.com for a delivered price.