Table of Contents
Overview
MFM Wind & Water Seal Underlayment is a self-adhering roof underlayment with a non-slip polymer film. It is intended for secondary waterproofing.
However it is presented as ideal for protection against ice dams and wind-driven rain. In addition it uses a high-temperature, rubberized asphalt adhesive. Next it is protected by a split release film that is removed once the underlayment is installed.
Also it focuses on high adhesion for ease of application. As a result it targets elimination of water movement under the membrane. In addition it is intended as secondary waterproofing and it is positioned for protection against ice dams and wind-driven rain.
You can reference the self-adhering roof underlayment here.
Key takeaways
- Uses a non-slip polymer film and a high-temperature, rubberized asphalt adhesive.
- Supports secondary waterproofing and protection against ice dams and wind-driven rain.
- Includes a split release film that is removed once the underlayment is installed.
- Lists overlapping guidelines for easy installation and self-sealing around fasteners.
- Buyers commonly describe very strong adhesion, positive material quality, and a heavy roll.
What the product is designed to do
This membrane is designed for secondary waterproofing under roofing material. Also it is positioned for protection against ice dams and wind-driven rain.
It is designed to self-seal around fasteners once it is in place. In addition it supports elimination of water movement under the membrane.
It is applicable for use under any roofing material. Next it is compatible with most sealants and primers.
For more context on peel-and-stick roof membranes, see this roof membrane review.
Materials, dimensions, and technical details
The underlayment uses a high-temperature, rubberized asphalt adhesive. Also it includes a non-slip polymer film and a split release film.
| Detail | Technical detail |
|---|---|
| Roll length | 67 ft. |
| Roll width | 36 in. (3 ft.) |
| Roll coverage | 200 sq. ft. |
| Roll thickness | 40 mils |
| Roll weight | 52 lbs. |
| Product dimensions | 36.33 x 8 x 8 inches |
| Test method codes | ASTM D 5147, ASTM D 1970, ASTM E 96, ASTM D 903/1970 |
If you want to keep the same product link in your material list, use Wind & Water Seal underlayment roll.
Installation and placement notes
Installation uses the split release film during positioning. Also the release film is removed once the underlayment is installed.
The membrane includes overlapping guidelines for easy installation. Next those guidelines support alignment as the membrane is applied across the deck.
Application is recommended in temperatures over 50°F on decks with a minimum slope of 3:12. However a minimum slope of 2 in. per foot for installation is also listed.
It applies to plywood, OSB, foam insulation, house-wrap, rigid vinyl, and masonry when the surface is clean and dry. In addition it is compatible with most sealants and primers.
This membrane is a vapor barrier, so proper ventilation during installation matters. Next it is most effective when stored out of direct sunlight.
Once applied, it needs to be covered within 60 days of installation. For example this timing matters when sequencing roofing material over the membrane.
Performance characteristics described
The membrane features high adhesion for ease of application. Also it targets elimination of water movement under the membrane.
The adhesive is described as high-temperature, rubberized asphalt. In addition it is described as will not crack or dry.
It is described as high elongation and flexible. Next it is described as able to accommodate the contraction and expansion of the application surface.
It is self-sealing around fasteners. Also it is applicable for use under any roofing material.
For readers comparing membrane styles across roof and flat-roof contexts, see this waterproofing membrane guide.
To keep one consistent purchase reference, use MFM Wind & Water Seal Underlayment.
Review patterns buyers commonly mention
Buyers commonly describe adhesion as very strong. Also material quality is described positively.
The roll is commonly described as heavy. However some buyers describe handling as challenging when the membrane sticks to itself or other surfaces.
Pros
- High adhesion for ease of application is a stated feature.
- Self-sealing around fasteners is a stated feature.
- Overlapping guidelines for easy installation are included.
- Buyers commonly describe very strong adhesion and positive material quality.
Cons
- Buyers commonly describe the roll as heavy.
- Some buyers describe handling challenges when the membrane sticks to itself or other surfaces.
FAQ
What is this underlayment used for?
It is intended for secondary waterproofing. Also it is positioned as ideal for protection against ice dams and wind-driven rain.
What surfaces can it be applied to?
It applies to plywood, OSB, foam insulation, house-wrap, rigid vinyl, and masonry. In addition the surface needs to be clean and dry before application.
What installation conditions are listed?
Application is recommended in temperatures over 50°F on decks with a minimum slope of 3:12. However a minimum slope of 2 in. per foot for installation is also listed.
Does it need ventilation during installation?
It is a vapor barrier. As a result proper ventilation during installation is required.
How soon does it need to be covered?
Once applied, it needs to be covered within 60 days of installation. Next plan the roofing material steps so the membrane is covered within that window.
How is it stored before use?
It is most effective when stored out of direct sunlight. Also keep the roll protected until it is ready for installation.