Flat Roofs FAQUpdated a month ago

Application

Question: Which products do I use to waterproof my Flat Roof? 

Answer: You can use Liquid Rubber Color Sealant (comes in colors, greater elongation), Liquid Rubber Waterproof Sealant (good for constant submersion, most puncture resistant) or Liquid Rubber Silicone Roof Coating (1 coat application). You will also need Liquid Rubber Seam Tape/Geo-Textile and/or Liquid Rubber Caulking.

Answer: We do not recommend applying to tar and gravel roofs as this will require a greater skill set and far more material than most people have. You may need to consult a roofing professional for these.

Answer: Do not apply to Coal Tar roofs. You will need to remove the coal tar or apply another coal tar product over these types of roofs.

Question: How much do I need?

Answer: How much sealant you need depends on the specific product and the project it is being used for. For example: A roof with a pitch greater than 3/12 will require 1 gallon per 30 sq ft when using Liquid Rubber Color Sealant, while for a roof with a pitch of 3/12 or less you will need 1 gallon per 15 sq ft. See coverage rates below:

Answer: To determine how much sealant or primer you need, divide your total square footage by the coverage rate provided. Example: You have a 300 sq ft of metal roof and the Color Sealant coverage rate is 1 gallon per 30 sq ft.  so 300/30 = 10 gallons of the Color Sealant. (Apply in multiple coats until all material has been used.). Coverage rates are expressed in final coverage and will include all coats needed to achieve membrane thickness.

Answer: Other factors to consider are that roof pitch and profile (a rougher profile will take more material than a smooth roof) and loss (material that is spilled, left in pails and on rollers and brushes, or lost in transmission when spraying) usually calculated at 5-10%

Question: Do I need Seam Tape or Geo-Textile? 

Answer: Yes. These products are used over the seams, around penetrations, etc. where a leak is most likely to occur. These products reinforce your coating at these area's to protect them from cracking during thermal and other movement.

Question: Which is better, Seam Tape or Geo-Textile? 

Answer: Seam Tape is the premium product as it offers it's own waterproof layer as well as a fiber reinforcement and is applied by peeling off the backing and pressing onto the surface. Geo-Textile will do as well as it offers a fiber reinforcement but it will require a bit more labor to install as it is applied via the 3-course-method. Click here for an example.

Question: Do I need Primer? 

Answer: It depends on what kind of roofing material you are coating. EPDM and TPO roofs require that you use Liquid Rubber EPDM & TPO Primer. PVC, aluminum/tin, concrete and wood  roofs require that you use Liquid Rubber Multi-Purpose Primer.

Answer: For mod-bit (torch-down/roll-down) roofs primer is not commonly needed for adhesion, though a bleed-blocking primer may be needed when applying a white or colored product to prevent bleed-through.

Question: How do I clean my roof? 

Answer: For EPDM, TPO, PVC, aluminum and fiberglass roofs you can use Liquid Rubber RV Smart Cleaner. Be sure to refer to the application guidelines for more information.

Answer: For Concrete and wood roofs you can use Liquid Rubber Deck and Patio Cleaner . Be sure to refer to the application guidelines for more information.

Answer: Mod-Bit (torch-down/roll-down) roofs are a little tricky as it can be easy to trap moisture under the surface and power-washing can damage the existing material. Compressed air can be used (again watch out for damage) and roof sweepers. Be sure to remove any moss/lichen that is present and treat the area with a mild bleach solution as these become rooted in the surface. Grease/oils must be cleaned with a degreaser or cut out and patched.

Question: What tools do I need to apply my Liquid Rubber products? 

Answer: You can use a brush or 10mm (3/8") nap roller or push broom.

Answer: It is also possible to be sprayed with airless, heavy industrial spray units capable of spraying a bitumen coating (e.g. Graco GH833), however, most homeowners will not have access to this equipment. 

Question: Do you have application guidelines/instructions to help me with my installation? 

Answer: Yes. Application guidelines can be found on our project pages (click here) or in the Application Guidelines and Technical Sheets section of this Help Center.

Question: Do you have application videos to help me with my installation? 

Answer: Yes. Application videos can be found on our project pages (click here) or on our YouTube channel (click here).

Question: What should I be looking for when first inspecting my roof? 

Answer: Look for damaged sheets (often at upturns), failed seams, blisters (where the system has become unbonded from the substrate) loose or damaged vent boots/caps/flashing/etc., deterioration caulking and previous repairs, discoloration and drainage issues (e.g. ponding, working gutters), improperly installed drains (e.g. sits too high), moss or lichen, trapped moisture (use an infrared scanner). 

Question: Do I need a new brush/roller every time I apply a new coat?

Answer: If you wrap your brush/roller in plastic (e.g. a grocery bag) you will slow down the curing process and you should be able to use the same brush/roller for your next coat. You can go a step further and place the plastic bag in the refrigerator (Do not allow contact with food)

Question: Can I coat over an existing coating or paint?

Answer: You can apply our bitumen's over both bitumen and acrylic coatings, but it is not recommended to apply our acrylic or silicone coatings over a bitumen without a bleed blocking primer.

Answer: It is recommended to remove oil based or recently applied coatings with high solvent content prior to applying your Liquid Rubber products. (oil and water don't mix and solvents can deteriorate our water-based coatings). Do not apply over coal tar.

Question: Can I apply one of your cheaper bitumen coatings first then coat over that with a white or colored product?

Answer: No. These are not compatible chemistries and will not provide and adequate bond. The bitumen will also eventually bleed through the colored coating.

Question: What if I have a problem or question with an application?

Answer: Our technical support team is here to help you, just reach out to call. email or chat with one of our representatives.

Answer: You very well may find the answer you are looking for in one of our application guidelines, which can be found on our project pages here.

Question: Does it come with a warranty?

Answer: Most flat roof applications come with a 5 year warranty when properly applied.