Hi,

I have a rental duplex with a low slope tar and gravel roof. I have had three quotes with three different materials.

The three quotes had different square footages but were within a 100 feet of each other.

Approx 2900 - 3000 square feet.

No taxes included and of course, any unforseen work would be extra.

1) Replace tar and gravel with tar and gravel. Approx $22,000.

2) Spray 2 inches of foam and coat with an ultraviolet coating. Needs recoating every 5 years. Adds r14 insullation. Approx $18000

3) Thermoplastic membrane with approx 235 linear feet of new metal edging. Approx $23,500

I'm in Canada so prices are higher but I just think these quotes are way too much. Not that I have much choice though.

I'm leaning towards the spray foam but the membrane guy told me that even if I don't buy from him, dont' use the spray foam as they replace roofs done with it all the time.

Any opinions on cost or best solution?

 

option 1- what does it involve? power sweep the old gravel and place two new felts set in asphalt or complete tear off and replacement. big difference between the two.
option 2 - assuming you are not my worst enemy in the world; I would not suggest the spray foam. bad product.
option 3 - thermoplastic in what mil thickness? will they be doing a tear-off and adding new insulation or just putting down a recovery board and placing the new membrane? fully adhered, mecanically fastened or ballasted?

More questions: is the existing roof leaking? If so remove it to remove the moisture regardless of what system you choose. if you trap moisture under a new roof you will destroy the new roof from the inside out.
Do you pay the heat on the rental? if so add insulation to save yourself some money. If not then it is up to you.
I am not sure about prices for residental low slope roofs but for commercial work the numbers you received are reasonable (or even cheap) for our area.

 

Well I went ahead with a roof.

Its called a torch down.

They power swept the gravel, then chipped it down.

They said they could not strip the old roof off because it was too thin. I did not understand that but I don't think thats a problem as the old roof never leaked yet but it had some bad spots. I thought that was ok to do. They did strip two feet around the edges. Previous owner had work done and they had just poured tar along the edges as a remedy. It was 2 or 3 inches thick.

They mopped it, put down stryofoam insulation with an r value of 6.5. The foam had foil on one side.

They put 1/2 inch particle board over the foam and mopped again.

They put down torch down ashphalt roofing in about 3 foot strips.

They took off the metal flashing along the edges and put strips of rolled roofing over that.

They installed 3 skuppers on the south side and drop down drains on the north end.

Total cost was $19500 plus 5% tax.

Total square feet was 2975. There was a 3 foot overhang all around that we did not insulate as it was a waste in my mind and also, I would have needed new flashing because of the added height of the insulation.

It looks good and waterproof but what do I know.

So I don't know. Seems like a fortune for a roof. I had a quote buy trusses and then I would have put them up but that would take me forever and I'm too busy. Also, would have needed to extend all the plumbing vents and chimneys plus build a pony wall for the trusses to sit on as they could not sit on the soffit overhang.

 

I think you chose the route I would have. Not cheap, but (hopefull) effective. And every nickel you spend on the place helps come income tax time, right?

 

It does help at tax time. Get about 40% back if I can claim it as a current vs a capital expense. But a new roof is like a water pump in your car. Does not add value but takes away value if its broken.