Pembroke: House Wrap: What it is and how you use it.

By: Terry Quinn, CS, CAPS, CGR, VSI (Almar Building & Remodeling Co. Hanover Ma)


Vinyl Siding is not Water proof! So you need an underlayment to protect your house when moisture gets under the siding.


House wrap for Vinyl Siding

House wrap for Vinyl Siding

That’s why we use house wrap. House wrap is a synthetic material used in building today to replace standard tar paper underlayment hat was used in years past.   It is a weather-resistant barrier that improves buildings energy efficiency and it helps stop moisture from entering the house and allow water vapor to escape to the outside which will keep the R-value of the insulation from dropping.A main purpose of house wrap is to prevent entry of moisture or rain into the wall cavity. MOST sidings are not water barriers. All GOOD house wraps provide waterproof protection when properly installed over the sheathing and behind the siding.


Advantages of house wrap are:

  • Provide U.V. protection
  • Most exceed code requirements for air and water protection
  • Save money on heating and cooling costs
  • Reduce air infiltration
  • Allow vapor to flow out of the building



  • If not installed properly, it will cause more damage than benefits.
  • Gaps or seams not sealed effectively will allow water to penetrate the building’s interior
  • It’s not a vapor retarder and should not be treated as one
  • Improper lapping of house wrap will cause mold and moisture problems

Don’t rely on the siding to stop the water. The purpose of siding is to look good and it does shed some of the water, but it also lets some in. Flashing and house wrap must shed that water and allow it to weep out from behind the siding and not wet the sheathing or framing which will cause rot.

Tyvek House wrap

Tyvek House wrap

Just some thoughts to consider when planning your vinyl siding installation. And remember the most important part of any vinyl siding job is to hire a proven, well established company to install your siding job, who has a long track record and is certified by the vinyl siding institute such as Almar Building and Remodeling or CAT Exteriors.

To get answers to more of your questions about Vinyl Siding you can watch our videos answering the top 18 questions we get from homeowners presented by Terry Quinn, for our exteriors division CAT Exteriors. Click Here:

Terry Quinn, CS, CAPS, CGR, VSI  is the President of Almar Building & Remodeling Co in Hanover Ma. Almar is a 3rd-generation, full service general contractor, and satisfying homeowners for over 53 years on the South Shore. Almar handles both large and small projects including: Additions, Kitchens, Bathrooms, Basements, Windows, Doors, Siding, Decks, and other carpentry projects. With 5 licensed constructions supervisors, Almar is also RRP certified to work on homes built prior to 1978. Visit the website for more information about Allison and Almar Building.  781-826-277


Craig Guido

With 20 years of remodeling experience both in the field and working in collaboration with homeowners to develop remodeling projects designed to fit your lifestyle.