I just replaced the entire rear of my house right down to the sill plate and currently have the rough openings for the windows and french doors, when putting on the house wrap i've seen some builders put a 10-12" strip of thick tar paper over the house wrap around all of the windows. Is this a good idea ? I'll be using cedar clapboards with 5/4 cedar trim around all windows and doors. Thanks

 

Make sure the windows are installed properly and flashed according to the manufacturers instructions. Not all windows are installed the same way. Just slapping up some tarpaper or Tyvek is not a solution and can lead to problems.

I do some moisture intrusion and moisture damage inspections and find that over 90% of the problems are with the installation/flashing and not with the window/door. Even pin-hole leaks in the wrong place can let warm, moist air out to where it condenses to water and accumulates enough for rot ot mold.

There is such a thing as a certified window installer. I think the window manufaturers, designers and some builder helped establish the program.

Dick

 

Some builders use tarpaper when flashing windows in stucco or EIFS installations. Since you will be using cedar lap siding and trim, you will want to use the preferred method of flashing new construction windows.

When you put the building paper across the rough opening, you first cut a horizontal slit across the top of the rough opening. Then you make a vertical cut half way down the center of the opening. Then from that point, you cut diagonally down to each corner. The building paper is to be wrapped around the interior of the wall, and its edges are to be sealed with contractor's tape.

Before the window is installed, you make a 6" diagonal cut away from the top left corner and the top right corner. You fold that flap up, and temporarily hold it with tape. They also recommend using a pan flashing or a flexible self adhesive membrane such as Tyvek Flexwrap. After that is installed, you then caulk the head and sides of the opening and install the window level, plumb and square. You then tape the sides and top of the nailing fin with a self adhesive membrane such as Tyvek Straightflash. Then you fold the flap of building paper down over the top of the nailing fin, trim it, and tape the edges of the flap with contractor's tape.

More helpful information can be found at:

http://construction.tyvek.com/en/index.shtml

 

I am familiar with this product. I sell a version of this called Protecto Wrap window installation tape. All it does is seal over the nailfin and exterior sheathing to help reduce air infiltration. It is extremely sticky and does help alot. I think it's worth the money, just make sure the window is installed properly before using tape cause it's kind of difficult to remoce afterwards.