Hire an engineer. Commercial buildings have their own set of rules and violating just one canresult in code violation that prevent's certificate of occupancy or bring the place down on your head. You should make sure you understand code before doing anything.

Seeing those wood beam repairs make me ask if you had the place inspected for compliance before buying? If those repairs were not permitted,you might already be behind the 8 ball.

We've already had a former inspector in to look it over and he said it's fine.

Having the place inspected pre-sale was wise. Many unsuspecting buyers have discovered their bargin commercial property is more of a liability and financial burden than asset. Commercial insurance and taxes alone can bleed an owner. New owners usually face required improvements that had been grandfathered for sellers.

Are you planning to rent it out as commercial or residential space? Regarding "keeping the commercial look", you could cut 2"-4" rigid foam to fit between the rafters, and paint the underside of the foam. This won't give you very high energy efficiency, but better than nothing. If you are looking at the underside off the roof deck, then you don't have much choice for increasing insulation.

We are in southern Indiana so humid summer and winter is a guessing game. We are looking to rent it out as a commercial space. We have a lot of work to do to the soace, but we knew it would be a project leading into it. As far as foam goes, are all created equal? I was looking up SIPS but it seemed that is something that should be done in construction, not after the fact like I’m doing now.

I used SIPS in the roof of my new construction home, and I see no way to retrofit. You could put SIPS on top of your roof and put new roofing on top of it, but if you're roof is flat, maybe that's asking for trouble. Is your wish to not cover the exposed beams a visual issue, or a desire to keep the ceiling as high as possible? I have exposed floor joists in my basement and am trying to figure how to make it more attractive, but keep access to the spaces between the joists; a drop ceiling would lower the ceiling height, so I think that's out.

Typically commercial flat roof insulation is done with polyiso panels on top of the roof. You could add them or increase the thickness of them when you re-roof the building. Rubber roof membrane then lays directly on top of the insulation. It probably does not make economic sense to tear off a good roof to add insulation.

Are those 2 X 6 joists on 24 inch centers held up with beams 8 feet apart? Did you notice the patched joists? The sistered joists don't reach the beam supports. That creates a 4 foot span with very little support. Has a structural engineer verified this is sufficient to hold the snow load in Indiana?

Are you planning to install the HVAC equipment on the roof? You need to verify the roof can support the additional weight.

I think this would be a good application for spray foam insulation. It could be open or closed cell depending how what R value you want to achieve. I would cover the foam with 5/8 inch sheet rock and paint the exposed beams. The sheet rock hide the electrical wiring and sprinkler system piping if it is required.

We will certainly look into the joists and structural safety. We will be under the scrutiny of our building commission and will do whatever they recommend. We will not place hvac on the roof. We want it more accessible. I like the way you think though, mike, with the sheet rock and spray foam. Thank you for your input!

Hi Nicole Neff,

Indy here. Of course I know S Indiana and what you are working with.

So a couple of things: The way this is often done is that the insulation is between the roof membrane and the deck - in other words outside the building. That only really works if you are replacing the roof - but keep it in mind.

Also know you may be looking at lead based paint up there. Get a test kit and test it yourself.

You may want to look at Insulation, electrical, HVAC, and possibly sprinkler in that space and then covering it, rather than trying to keep it original.

Jake, we have been fortunate to have a code consultant and evaluate our building, and should not have to have sprinklers. Thankfully! The more I think about the heat ($$$) loss, the more I think covering the exposed beams is worth losing a bit of the character. The roof is only 10 years old, and although not in perfect condition, should not need to be replaced for a while. I greatly appreciate your input! If we fine lead based paint, are there options for us to remove on our own?

Lead based paint: the law merely requires you to disclose it and supply this pamphlet for any building built before 1978 whether you sell it or rent it, you must disclose it to anyone interested in leasing or buying the building.

Lead based paint EPA disclosure pamphlet

EPA's Renovation Repair and Painting rule is intended to protect the health and safety of individuals who may be exposed to lead-based paints. While the rule applies to contractors, consumers disturbing lead paint would be well served to take health and safety precautions. Here's a link for guidance:

https://www.epa.gov/lead/renovation-repair-and-painting-program-consumers

You should also check with your waste disposal company to see if there are any special requirements for disposal of materials with lead-based paint.

Nicole Neff

Don't get too freaked out about the potential lead based paint - the truth is that it's everywhere.

I'ts particularly an issue if you have children putting things putting things in their mouth or if you are breathing the dust (from removal).

My point was that sometimes you can have multiple reasons to do something (Lead based paint, structural, electrical, insulation) - whereas a single issue (insulation) may not justify enclosing the ceiling.

If it were me, I'd need to have a better understanding of any potential structural issues (are all the beams in good shape, etc). If there's no other compelling reason to enclose it, I'd keep it open and see how it goes.

I'm going to guess you don't have insulation in those walls either - that they are solid brick.

The good news is that this isn't residential - the tenant doesn't have to maintain warm temps at night.

If you don't insulate, you can help the tenant maintain reasonable heating costs by installing a 92% or better gas furnace with outside air intake - a setback thermostat and double pane windows (if you can do that and still keep the historic look).

I watched a This Old House episode this weekend where they were super-insulating the roof as part of a Net-Zero renovation. You might want to take a look at it just to see what they did.

They first installed standard OSB roof decking, and then a snow/ice barrier. Then on top of that they made a perimeter frame and added five inches of rock wool insulation. Then they nailed on a 2nd roof deck and installed underlayment and shingles on that. When they got done they had a roof that must have been about 6 1/2" thick. They also sprayed foam on the underside of the roof deck, but admitted that it was probably overkill. By the time they got done I think the R value was around 50.

Bruce

I was thinking about the same TOH episode when I saw this original post!