There are many house wrap products available and even why you would need house wrap. Moisture management, air barriers and wind reduction are some of the key benefits of a good house wrap. If you understand the benefits, you would never want to install siding without it.
Some builders and remodelers will skip house wrap all together — that is a mistake. A good house wrap goes over the exterior sheathing of a house but below the siding. It creates a way for moisture that can get behind the siding to escape.
Moisture collects behind siding in several ways.
- Moisture in the air from inside of your home. This can be from every time you flush a toilet to running water in a sink.
- Moisture from the outside of your home. This can happen from any cracks or gaps which may not even be visibly noticeable.
- Moisture from condensation. If the temperature varies from inside of your energy envelope to the outside, when warm moist air comes in contact with a cool surface, moisture from condensation is sure to follow.
These issues don’t have to be a problem if you manage them well. In northern climates it is common to have a non permeable vapor barrier such as plastic sheeting (also called visqueen) on the inside
of the studs between the insulation and the drywall. This is because you don’t want the warm moist air to condensate inside of the walls. That vapor barrier reduces the amount of moisture that can get into your insulation and create mold or moisture problems in the insulation itself. Wet insulation has a reduced R-factor, the measurement used to identify the resistance to energy loss. Is this a perfect system? No. Even a vapor barrier must be pierced when the nails or screws hold the drywall tight to the studs but if done well and with as few unnecessary holes as possible, sandwich the plastic sheeting between the stud and the drywall.
There are many house wraps in the marketplace today and technologies are constantly changing and improving. A well known house wrap that was the industry standard 20 years ago, is not used today by most of your better remodelers as there are better technologies available.
One of the best house wraps out there is Raindrop by GreenGuard. When properly installed, it has channels built right into it that can move any moisture that does get behind the siding, down along the wall to a place it can escape along the bottom.
For a good understanding of best practices, check out House wrap for moisture protection on our youtube channel.