Mixed Use Building, Attaching a Deck, and a Flat Roof

This Tuesday’s blog is a Bonus Ask the Guru discussing some mixed use ideas for a gallery and apartment, attaching a deck, and a flat roof design.

DEAR POLE BARN GURU: I’m looking for a mixed used building, Large open plan space ground floor for an art gallery and two two bedroom apartments on second floor. Maximum height 32 feet x 25 long x 28 wide. Front of gallery space with large overhead door, with glass or polycarbonate windows. SALVATORE in NEW PALTZ

DEAR SALVATORE: I see you have been working with Hansen Pole Buildings’ Designer Erik on your proposed project. There are a plethora of options available to you. One challenge is going to be it will be impossible to create a space with two, two bedroom apartments within a 700 square foot area.

Facing reality, you will only be able to have a single (and small) two bedroom apartment.

Let’s work downward from your 32′ maximum height. Ulster County happens to be in Seismic Zone 6A, where 2021 IECC (International Energy Conservation Code) requires R-60 ceiling insulation. Blown in fiberglass insulation will need to be 20.5 inches deep (according to Owens Corning). Allowing for at least a minimum of an inch of clear air flow above, you will need to have roof trusses with 21.5 inch raised heels.

A 4/12 slope gabled roof will rise 50″, so now we are down to 25′ 11.5″. To attain an eight foot finished ceiling will take 8′ 1-1/8″. 25′ clearspan floor trusses and 3/4″ sheathing will be 18-3/4″ thick.

This would allow for a main floor ceiling height as great as 16′ 6″ after allowing for a nominal four inch slab on grade. Obviously it is not a requirement to have this sort of height, but this does provide some ideas.


DEAR POLE BARN GURU: I’m looking to add a covered deck to my barndo. The interior was built up off the ground so it has a crawl space. I’m just wondering if I can attach a deck to it and what would I need to do in order to do so seeing how my posts are 8 ft on center and I have no rim board like a traditional home to attach my ledger to? I haven’t talked to my building department yet. Just trying to get an idea before I go up there, thanks! MATT in INDIAN RIVER

DEAR MATT: Due to a plethora of deck failures in recent years, building codes have been adopting new and much more stringent requirements for attached decks – this includes making it near impossible to just have a simple ledger/rim board attachment, without some serious Simpson hardware. You could also be creating a situation where existing wall columns and/or their footings become over loaded due to deck weight. My best encouragement is to engage services of a Registered Professional Engineer who can evaluate your current structure and design a deck being both code conforming, as well as safe.


DEAR POLE BARN GURU: We have a flat roof 23′-0″ x 27′-1 3/4″. We would like to change to a roof with a small slope ( about 2.8 degrees) Does Hanson do plans? EMILY in BATON ROUGE

DEAR EMILY: Your roughly 0.59/12 roof slope will still be fairly flat, however with snow not being an issue, you should be fine with a built up roofing material or EPDM. We provide plans only for complete building material packages, so your request would be outside of our scope.

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