Search
Search
1419 results were found.
It is impossible to completely prevent the passage of water vapor through the ceiling and into the roof structure. Therefore, it is important to try to remove the vapor and deal with the condensation. This is done by providing an unobstructed vent area of not less than 1/300 of the insulated ceiling area.
Locate intake vents/screens at the soffit openings, making sure that the ventilation area is evenly distributed and as high as possible at the ridge. This method takes advantage of the chimney stack effect in promoting good air movement.
Ventilation at the soffit and ridge >>>
Moisture during construction
Moisture can also enter roofing materials while they are stored on the construction site. Roofers should protect water absorbing materials, such as underlayment and wood (OSB, plywood boards), from rain or long periods of humidity. It is also not recommended to install very wet bitumen shingles on the roof.
Ice Damming
Ice damming is the build-up of ice at the edge of the roof, caused by heat escaping from the house and melting snow. This melted water flows down underneath the snow covering the roof. As it reaches the outer edge of the eave over the unheated soffit, it freezes, creating an ice dam. The ice dam stops the flow of melted water from reaching the eave. Ice then builds up in the form of icicles and slabs, and the melted water can back up through the shingles and leak into the attic (see drawing). Ice build-up also causes structural damage to the eave and the roof and can be a potential hazard to passers-by.
Water leakage caused by ice dams >>>
Take the following measures to help prevent ice dam problems:
- Provide eave protection, and impervious IKO Armourbase Stick underlayment, at eaves and in the valley intersections, to stop water from penetrating through the shingles because of ice damming (see drawing). Armourbase Stick has good waterproofing properties: it is W1 ranked and has average values of 4 m in the water column test. Thanks to the bituminous compound, the underlay can enhance its waterproofing behavior and form an excellent prevention against ice damming.
- If the roof is insulated between the rafters, don't forget the ventilation gap above the rafters, which is created by the contra-batten, and sufficient intakes at the eaves.
- With a cold roof system, keep the attic space cold by insulating it from the warm house interior. This will reduce or eliminate snow melting.
- In case there are no snow stoppers mounted on the roof and the snow slides freely and falls from the roof, ensure that the outer edge of the gutters is lower than the slope line to allow snow and ice to slide clear (see drawing). It must always be safe, to avoid danger for passers-by.
Place gutters below the slope line to allow snow and ice to glide clear. >>>
Following these guidelines will help you reduce the risk of roof problems. More roof problems such as typical roof failures and flashing problems will follow in the next blog. Stay tuned!
Interested in the products mentioned in this blogpost?
Successful roof projects require that the roofer follows the correct application methods. If he doesn’t do the job properly, the final effect will look poor. Even the best and most expensive roofing material cannot help when application instructions aren’t followed. Most importantly, every minor mistake can cause leakage. Every roof repair contributes to decreased lifespan of your roof (and it can be quite expensive as well!). We'll be explaining the most prevalent roofer mistakes.
In the next 4 blogs we’ll be summing up some of the most common mistakes so that poor workmanship can be avoided. Let's start with the following 5 topics:
1. Absence of or incorrectly installed starter strip
2. Improper slope
3. Incorrect shingle overhangs at the eaves
4. Neglecting installation of drip edge flashing at the edge
5. No or improper installed underlayment
1. Leaving out the starter strip or applying the starter incorrectly
The incorrectly installation of the starter strip (or worse, the absence of the starter shingle) brings many problems. You risk water infiltration at the eaves and shingles from the first row can be blown off. It can also cause aesthetical failures
Solution:
If you are missing the starter strip, try to slide a new piece under the shingles of the first course. This new starter strip should be secured with nails and glued with bituminous mastic. Shingles and starter strips at the eaves must always be glued and protected against wind blow off.