Home Roofing Products Asphalt Cements & Coatings > Mastics 251 Premium Wet/Dry Elastomeric Flashing Cement

251 Premium Wet/Dry Elastomeric Flashing Cement

251 Premium Wet/Dry Elastomeric Flashing Cement

251 Premium Wet/Dry Elastomeric Flashing Cement

Tenacious under extreme conditions, Mule-Hide #251 Wet/Dry Elastomeric Flashing Cement is a cold-applied bonding agent formulated for making wet repairs of leaks in many asphaltic roofing membranes and SBS modified bitumen roofing systems. Fortified with SBS rubber, it is ideal for sealing and patching temporary emergency holes and cracks in roofs, even in standing water. It also can be used to make emergency repairs on built-up roofing (BUR) systems, shingles and concrete, as well as for general damp-proofing.

  • Used to install SBS modified bitumen membrane flashings to parapet walls, curbs, and roof penetrations.
  • Ideal for making waterproofing repairs, particularly in moving joints.
  • Seals laps and perimeter edges of self-adhering modified bitumen membranes.
  • In repair applications only, it may be used as a topical application on smooth or granulated APP modified bitumen roofing products.
  • Repairs splits, breaks and small holes in asphalt-based roofing and flashings in wet and dry conditions.
  • Can be used to install metal edge flanges and seal gutter seams, air-conditioning ducts and other metal joints.
  • Can be used for positive-side damp-proofing of concrete, masonry walls, and foundations.

  • ModBit
  • M&R
FIND A DISTRIBUTOR
Features Documents Options Application FAQs

Features & Benefits

  • Adheres to most surfaces in wet and dry conditions
  • Great bonding strength
  • Highly flexible to accommodate the temperature-related expansion and contraction of the roofing system
  • Heavy, trowel-grade consistency
  • Exceptional durability and performance over a wide range of challenging temperatures and weather conditions. Will not mud crack and will remain highly resilient and durable through all seasons.
  • Interlocking fiber matrix ensures uniform, excellent adhesion.
  • Excellent sag resistance when used on vertical surfaces, even at high temperatures.
  • Does not damage conventional asphalt-based roofing membranes.
  • Meets Miami-Dade-County Standards

Documents

Options

Item ID Description Packaging Qty per Ctn Weight per Ctn Cover Rate
16MH2513 MH 251 PREM. WET/DRY ELASTOMERIC 3 GAL Metal Pail 1 30 8 gallons per 100 sq. ft. for 1/8"
16MH2515 MH 251 PREM. WET/DRY ELASTOMERIC 5 GAL Metal Pail 1 49 8 gallons per 100 sq. ft. for 1/8"

Application

Application Example Image

FAQs

Mule-Hide #251 Premium Wet/Dry Elastomeric Flashing Cement differs from #231 in that it is polymer-modified, meaning it is more flexible and higher-performing in low-sloped commercial applications than #231. #251 differs from #241 in that #251 is formulated for functionality in wet applications, where necessary, and is contains premium-grade polymer modifiers. #251 is the premier repair compound that is easily spread and applied to repair splits, seams, cracks and holes in spudded gravel, mineral surfaced cap sheet, smooth surface asphalt roofs, and most SBS andGranulated APP membranes. The modified properties provide excellent adhesion, elongation and recovery characteristics. Contractors seeking the highest quality, modified asphalt flashing cement with wet/dry functionality choose this product for commercial, low-sloped or steep-sloped roofing applications.
The coverage rate for Mule-Hide #251 Premium Wet/Dry Elastomeric Flashing Cement is approximately 8 gallons per 100 sq. ft. for a 1/8-inch (3 mm) coat applied to both surfaces. (All values are approximate and may vary with ambient temperature and job conditions.)
Mule-Hide #251 Premium Wet/Dry Elastomeric Flashing Cement can be applied using a pointed trowel, a wide-edged putty knife, or a gloved hand.
No. DO NOT USE Mule-Hide #251 Premium Wet/Dry Elastomeric Flashing Cement with PVC, TPO, EPDM or other single-ply roofing membranes.
No. DO NOT APPLY Mule-Hide #251 Premium Wet/Dry Elastomeric Flashing Cement over or under expanded polystyrene insulation.
No. DO NOT APPLY Mule-Hide #251 Premium Wet/Dry Elastomeric Flashing Cement under an APP modified bitumen roofing membrane with a burn-off film.
With proper storage, the shelf life of Mule-Hide #251 Premium Wet/Dry Elastomeric Flashing Cement is 24 months from the date of manufacture.
Mule-Hide #251 Premium Wet/Dry Elastomeric Flashing Cement should be stored at a temperature of at least 45°F but not above 120°F. It should be stored at room temperature for at least 24 hours prior to use.
Mule-Hide #251 Premium Wet/Dry Elastomeric Flashing Cement should only be applied when the ambient temperature is at least 45°F and rising. Cold weather can result in uneven application and improper curing, and it will cause the product to stiffen, making application more difficult. Application is not recommended if the substrate temperature is above 140°F.