Roofing procedures comparison


I got a water leak on the ceiling over the weekend. We have asked a couple contractors to come and estimate the work. Both estimates are about 8k-10k; however, I don’t quite understand the material/procedure listed in the contracts. Could anyone help picking which procedure is better for the roof? THanks so much!

A little bit about my roof:

It should be about 15+ years old and it’s a built up flat roof.

Contract #1:

  1. Strip off old roof, and haul away all debris.
  2. Sweep clean existing roof.
  3. Replace dry rots roof deck as needed. ( up to 200 Sq )
  4. First layer Flintlastic APP base complies, heat weld base sheet to roof deck.
  5. Second layer Flintlastic GTA finish (granular finished surface in your choice of color), heat weld
    The membrane to the base sheet with an overlap of 3” at the seams and 6” endlaps. An additional
    ply of Flintlastic STA Mid-ply membrane applies, drain boxes, all roof jacks, air-vents.
    a. Replace all ventilation air vents. (aluminum).
  6. Replace all roof jacks (sheet metal) and drain outlet.
    a. Install new galvanized gravel stop edging.
  7. Seal all roof projection with flashing compound.
  8. Third layer of Flintlastic GTA, heat weld over galvanized metal edging.
  9. Clean up all debris caused by our work.

Contract #2:

  1. Remove entire tar and gravel main front over­hang and rear lower roofs to sheathing boards. If the complete roof
    removal is not feasible to complete because of the solid attachment to the wood, the roof shall be removed down to
    the workable surface from the flat roof. Sweep and clean off all dirt and debris.
  2. All the sheet metals such as roof JACKS, VENTS, CHIMNEYS WILL BE REPLACED WITH NEW.
    a) 1 Layer of CertainTeed Flintlastic ­SA Nailable Base sheet.
    b) 1­Layer of CertainTeed Flintlastic­SA Cap sheet by self­adhering.
  4. ANGLES, WALLS, DRAINS and roof penetration area will be covered with:
    a) Install 1­layer of CertainTeed Flintlastic­SA nailable Base sheet.
    b) Install 1­layer of CertainTeed Flintlastic­SA Mid ply sheet
    c) Install 1­layer of CertainTeed Flintlastic­SA Cap sheet by self­adhering.
  5. New galvanized metal flashing shall be installed all around outside roof edges.
  6. Clean and remove all debris and all surpluses from the ground and roof area.
  7. Provide necessary safety devices and Worker’s Compensation and Liability Insurance during this
    period of work.
  8. Carries workmanship guaranteed for FIVE (5) years and Twelve (12) years of material manufacture
    warranty from the date of work completion.

Sounds like you live in California or Texas…

So, those are ‘similar’ roof systems ans scopes of work. First the roof systems- contract 1 is offering a 2 ply APP modified roof that will be torched in place, and contract 2 is offering a 2 ply APP modified roof where the base sheet is nailed to the deck, and the cap sheet is a peel and stick product adhered to the base sheet.

So, there isn’t anything wrong with either system, but I have some concerns: first, torching a base sheet to a wood deck (assuming you have a wood deck based on info in contract 2) is wildly dangerous, and comes with a huge risk of burning your house to the ground… System #2 is kind of a low end roof, the base sheet provides no real waterproofing, and peel and stick cap sheets are just ‘junky’ in terms of longevity.

Here is what I would do, and it shouldn’t change the cost at all- instead of using a nailable base sheet use a self adhering base sheet (prime the deck as all manufacturers recommend) and torch apply the same granulated cap sheet- this is a solid roof system, and once the cap is torched in place that base sheet will be fused to the deck like nobody’s business!

Couple more things- I like the flashing detail spelled out in contract 2 where they are flashing in everything with an interply. You basically want to make sure you have 2 layers over all the metal. Next, contract 1 refers to flashing penetrations with “flashing compound” get clarification on what that is and how it’s done- sounds a lot like “goop on some roof cement” which isn’t going to work at all… Lastly, contract 2 talks about removing the existing roof down to a suitable work surface- I would just make sure the don’t use that as ‘an out’ to not tear off the existing roof.