Do you have a strange leak?  By strange, I mean, does it happen only after a prolonged period of rain (e.g. a couple of days) or say when the snow starts to melt in spring?   If it were a problem with the roofing material, wouldn’t it leak every time it rained?  Maybe it not your roof!

We were working on a renovation siding job a while back.  We just started the tear off to begin the renovation, when our hearts dropped into our stomachs! We could hardly believe what we saw beneath the old siding. There was barely any building paper on the structure at all!

And the paper that was there, was installed incorrectly, layered so that it was catching water instead of repelling it! In other places, the haphazard paper didn’t even touch the neighbouring paper around it, leaving large sections of the sheathings open to the elements.

It was as if putting on building paper had only been a suggestion to the previous installers.

Building paper installed incorrectly

Building paper NOT installed properly. Paper should overlap and create a water resistant barrier.

Building paper installed incorrectly in Gable

Building paper doesn’t even cover the step flash on the roof. What were those installers thinking?


We asked if there had been any strange leaks in the house. Our homeowner couldn’t tell us if there had been any leaks reported because;

a) It was a rental property and

b) It was a new purchase for him.

Lucky for him as we worked our way around the house, we found that there had been minimal damage done over time. He was extremely happy we had caught such a HUGE mistake and that we took extra care installing the new building paper correctly.

How to install building paper correctly

After we installed Tyvek home-wrap correctly!


This is not the first time we have run into this problem. We see it over and over again on New builds done by inexperienced siding installers & on Renovations where the installers have ripped or torn sections of the old building paper and believe that they do not have to re-install a new building paper system because there is already one there.

How to install building paper correctly

Properly installed Tyvek paper over the step flashing on the roof.


Contrary to popular belief Siding doesn’t make your house water proof. You must have properly installed building paper fitted to your structure to help repel water.

How to install building paper, insulation and Siding materials

Create a water resistant barrier

Building paper like Tyvek or Black felt paper’s major function is to protect the sheathing against moisture infiltrating and allow some air passage so the wall cavity can breathe. The paper blocks water from entering the house from the outside but allows moist air to escape that could potentially lead to mold or rot.

How to install building paper correctly:

  1. ) Install home-wrap in the correct order! (start at the bottom and work to the top) You want water to travel downward at all points. DO NOT lap your paper the wrong way. You don’t want it catching or forcing water behind the paper.
  2. ) Install flashings over windows, doors or battens as required by local building codes. Make sure your paper overlaps the metal flashing in the correct order.
  3. ) Ensure your paper laps a minimum of 4” on horizontal seams and a minimum of 10” on Vertical seams. (check your local building codes for minimums in your area)
  4. ) If you are using Tyvek tape the vertical seams with Tuck-Tape or Dupoint tape (designed to work with that particular home wrap system) but leave horizontal seam open so water can free flow down and out from your structure.
  5. ) Pull the wrap tight when you install it to prevent creases or ugly paper bumps that can cause waves under the newly installed siding.
  6. ) You should be able to read the words.  The words on the fancy home-wrap product are not just there to advertise for the producer, they are are to indicate the correct side of the paper to face outwards. Tyvek inparticular has a specially engineered surface that should be placed with the grooves facing outwards in a vertical direction.

An oversight in the installation of the home wrap system can cause untold amounts damage and expenses in your future. This is why it is so important to hire a qualified siding installer when building or renovating your home.

Minimize your potential of installation errors and call us today!
Big or small we are the right team to call.

For all your exterior siding, vinyl siding and hardie siding projects. Serving Didsbury, Sundre, Olds, Carstairs, Cremona, Watervalley, Cochrane, and Airdrie.
10-31342 Rge Rd 43A
P.O. Box: Box 5 Site 2 RR1
T0M 0W0