I4 - Exterior Finishes - LT #1 Flashcards
How is the wall sheathing paper installed?
Overlapped like shingles, with a min. 4” overlap both horizontal & vertical.
What is a sheathing membrane?
1) Moisture barrier made from building paper or house wrap
2) Second plane of protection
What are three sources of rainwater penetration of cladding?
1) Direct contact from wind-driven rain
2) Gravity running down a surface
3) Bounce from rain hitting a surface
Why is face-sealed cladding unreliable?
1) Poor attention to sealing details at joints
2) Building settlement
3) Lack of maintenance
How is the wall sheathing paper installed?
1) Overlapped like shingles, with a minimum 4” overlap, both horizontal & vertical
What are the three components of a rain screen?
1) Moisture barrier
2) 10 mm capillary break
3) Exterior cladding
Why are vent spaces not continued around the corners of the building?
Pressure may not be equal around due to the wind
What type of strapping is normally used to make the vent space?
10 mm x 38 mm CCA treated plywood strips
What do the acronyms EIFS and LAB stand for?
Exterior insulated finish system, LAB liquid applied barrier
Main protection against liquid entry?
Exterior cladding
Differential pressure & wicking can suck water through small openings, what will reduce this?
Providing a capillary break
The capillary break is also known as
Rainscreen
Capillary break is
10 mm gap between inside face of cladding & building wrap
What is the most important component of a rain screen?
Maintaining an effective drainage space behind exterior finish
CCA plywood is more popular because treatment is CCA instead of ACQ
CCA less likely to corrode the fastener due to electrolysis
What can be used instead of stopping as a rain-screen?
Large mats can be used, non moisture susceptible
Why is ventilation good for a capillary break?
Allows for air circulation and help to dry
Venting the rain screen at each floor level can be dangerous why?
The moisture can vent into the roof soffit, important to use a drip flashing
Drainage should not
continue around corners or more than one story in height, it will create pressure differentials.
Sheathing paper most commonly used:
Most warranty providers call for two layers of 30 minute paper or one layer of 60 minute paper
Can rigid insulation boards be used instead of sheathing paper?
Yes
Where are Self-adhesive membranes applied?
Wherever moisture leakage is anticipated
Where are Self-adhesive membranes applied?
Wherever moisture leakage is anticipated
