Need Help Pricing A Job

I recently looked at a commercial flat roof on a restaurant that was completely rotted out. It’s 1000 sq feet (20x50) and the roof deck is 18 feet from ground level.

All of the OSB was gone. Nothing but saw dust left. The only thing left was a layer of TPO, a layer of EPDM, and a layer of soggy fiber board. No one should have been walking up there.

The rafters all have significant rot in the first inch and a half across the tops as well.

They want to do a complete tear off and the following…

1 - Replace or sister all damaged rafters that span 20 feet (16 OC 2x12).

2 - Build a raised low slope frame from front to back across the entire 50 feet.

3 - Add all new 3/4 CDX.

4 - Add 1" ISO board on top of the CDX.

5 - ADD 60 millimeter EPDM to top it off.

There’s also 2 large AC units and a walk in cooler compressor that will need to be craned off the roof. They would also like to remove a two old hood vents and a non working compressor that are no longer in use.

The walls around the perimeter are 2 feet tall and 140 total linear feet. I’m in the Chicago suburbs.

We can’t help you with pricing jobs because we don’t know your costs and every market is different.

You have a mess on your hands that sounds like it’s in excess of $2k/sq.

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Illinois and maybe local city would likely require a building permit since you would be making structural changes to the roof deck. That means engineering and permit costs.

You also have to figure out how you will do your fall protection. If the rafters are rotted you might not be able to rely on having a good surface to put a D-Ring into.

Local and state codes will also require at least R-25, and maybe R-30 insulation for above deck roof insulation and the finish slope will have to be a minimum of 1/4" per foot. That gives a 12.5" rise over 50’.

Building code requires edge metals to be ES-1 tested, so you will need at least 24 ga prefabricated metals unless you have had your own metals tested.

You will have to hire an HVAC contractor to disconnect the units and drain any refrigerant as well as the crane for getting the units off. Doing so with a completely rotted deck will be a challenge to say the least.

I wouldn’t touch a job like that unless I was making a hefty profit. The liability is outrageous in this case. One fall, one OSHA visit, and it will cost you more than your estimate came up with. Not to mention with engineering, permits, fall protection, HVAC, and crane you are already looking at 10-15k in costs, maybe more in that market.