Best modified bitumen

Roofing/Construction Questions
1

Hi,

I recently purchased a townhome in Washington DC. I’m getting quotes for contractors and most are pushing modified bitumen rather than rubber or EPDM.

What should I ask for when considering this material? 1,2,3 or 4 ply? I like the idea of a white granulated modified bitumen at 2 ply. The granulated is maintenance free and the white would reflect uv and heat better.

Also, how can I best negotiate with any potential contractor to get the price down? Thanks!

2
  • I also would like to ask whether I should get an APP or SBS mod. bit roof. Is the longevity better with an APP? Would a white 2-ply APP granulated mod. bit be the way to go?

I’ve met with two roofers so far who have quoted me 5,800 and 5,600 respectively for a roof on my 2,000sqft townhouse. I’d like to add 2 skylights on the roof as well which are ~600 a piece.

I am on Capitol Hill.

3

You can say “This is all I am willing to pay”…And if he is still in business when you have a problem,maybe he will come back…
That is the problem…People want a service,and want a good job,but want it cheap!You can’t get the best job done CHEAP…You can however get a quality job done for a reasonable cost…

4

poster could be a politcian.
first i do not like 2 and 3 layers of
anything unless it is hot tar with layers of
fiberglass mat.
torchdown last for 20 plus yr just one layer.
if water gets between the 2 layers it becomes
a big problem verses 1 layer were when it leaks
its easy to fix.

roll roofing whatever the style should not be
layered.

get one layer nice and tight with no leaks.
thats hard enough.

gweedo.

5

i have been doing modified for 25 + yrs & recommend atleast 2 inches of insulation, a 3 ply, with awaplan 170 white mop applied cap sheat on top of the 3 ply. it will look beautiful & outlast all of us. in that area call j&r roofing out of jessup, md.

6

I used to work with J&R quite a bit years and years ago. I believe they were the ones that roofed the White House if memory serves me correctly.

Anyway, I would recommend polyisocyanurate insulation, a coverboard like Densdeck or the cheaper alternative of perlite or fiberboard. Install a base sheet, 3-plies of asphalt BUR with Type IV felt and Type III asphalt, then install a reflective APP modified bitumen membrane. If you don’t plan on walking on your roof alot, and assuming you are willing to pay a little more, I’d recommend DerbiBrite by Performance Roof Systems. The APP membrane can either be torch-applied or set in cold-applied adhesive and only the laps torch fused together.

7

[quote=“1908townhome”]Hi,

Also, how can I best negotiate with any potential contractor to get the price down? Thanks![/quote]

Get multiple quotes and make your decision. If you want a good job don’t be so cheap. Jeez.

8

Where is your building insulation located? On top of the roof, or on top of the ceiling?

If it is a 1908 townhome, then its probably on top of the ceiling. Polyisocyanurate bord would not do any good in this scenario.

I would, however, agree with making sure you get a nice flat secure substrate down, though. You probably have a plank roof deck at thi point. Plank roof decks tend to porpoise over time. New plywood, or better yet, like Cerb said, a Dens deck recover board then a base sheet and mod bit cap. I like two layers of modified if youre not going to set the base in hot tar.