COMPONENTS OF A DECK COATING INSTALLATION
In order to further your education on the subject of decks, the following is a pictorial demonstration of typical deck components, including related materials that, if installed improperly, could mimic a deck leak. Please note that this is not to be construed as specifications for any job, material or manufacturer, consult your architect or construction manager for advice.
What we will take you through are the essentials for a good, leak free flashing and deck installation, utilizing a metal lath and acrylic concrete system. In all cases, but for decks in particular, proper flashing techniques are essential. Flashing must be installed in a weatherboard fashion, allowing for water to shed away from the building. Reverse laps in flashing and contiguous building materials, especially building and stucco paper, contribute to many leaks. Proper sequencing of the job is essential, scheduling the trades to coordinate this work can be difficult but must be done. You are advised to consult ASTM E 2266 44 Standard Guide for Low Rise Construction To Resist Water Intrusion for further information.
Often times decks are blamed as the source of a leak into the home when actually the leak is occurring from items near the deck-hose bibs and exterior electric boxes are the two most common items that leak. All penetrations must be flashed and caulked properly. Railings and walls are the next two most common items to leak, again, usually because of poor flashing and wrapping techniques. Recent technology utilizing Thermal Image Photography reveals these defects without destructive testing. A good page to see this in action is found at a contractors web site, The G.B. Group. This site shows deck and balcony leaks for the demonstration-testimony to the many claims and problems still occurring with decks?
1.
Deck ready for flashings to be installed. All edges and walls needs to be flush, plywood is nailed or screwed down, outside edge of deck just needs a stucco stop (3/4" x 1 furring strip) nailed on for fascia flashing to be nailed over.
“Picture Courtesy of Ron Webber, Pro-Coat Systems, Orange CA”
2.
Slope needs to be checked. One quarter inch per foot of fall is required by most manufacturer's (1" in 4') The picture above shows slope on the wall. Anything less and water will puddle on the deck and may cause problems.
“Picture Courtesy of Ron Webber, Pro-Coat Systems, Orange CA”
3.
Caulked lap at fascia, or drip edge. Lap extends over 4", a good sign.
A nail through the edge of the lap and this joint is ready for waterproofing.
4.
Here is a door pan installed. Note the lip in the background to keep water from leaking into the house under the threshold.
A generous leg allows the sheet metal man to lap his L metal over properly. Generous use of polyurethane caulk provides
assurance that this joint is tightly sealed.
“Picture Courtesy of Ron Webber, Pro-Coat Systems, Orange CA”
5.
A well sealed corner that can be a tough detail to properly flash and seal.
“Picture Courtesy of Ron Webber, Pro-Coat Systems, Orange CA”
6.
Here is a well sealed joint with the lathers paper down over the flashing running up the wall.
“Picture Courtesy of Ron Webber, Pro-Coat Systems, Orange CA”
7.
Here an installer is stapling down the metal lath to the plywood. Note the taped plywood seams.
“Picture Courtesy of Ron Webber, Pro-Coat Systems, Orange CA”
8.
Acrylic modified cement is troweled into the metal lath, covering it completely.
“Picture Courtesy of Ron Webber, Pro-Coat Systems, Orange CA”
9.
3/4 oz. Non Directional Fiberglass is then laid over the cement and a resin is rolled through the glass,
bonding it to the surface.
10.
A screed coat is troweled over the fiberglass and then a knockdown texture was sprayed out for slip resistance.
11.
For even more pizzazz, a tile pattern was done on this deck.
OTHER ITEMS THAT SOMETIMES ARE PART OF YOUR DECK SYSTEM
These are also essential and careful attention must be paid to properly detailing these items.
A post has been kerf cut to accept the flashing. Periodic maintenance must be performed, caulking the joints and keeping the post well sealed with paint or stain. Reject any wood posts that have a split in them, these openings will let water penetrate to areas below.
“Picture Courtesy of Ron Webber, Pro-Coat Systems, Orange CA”
Making it easy for the lather (stucco) to install his building paper in a weatherboard fashion is this large piece of sheet metal
that will allow paper to drop over the metal and and be slipped up underneath it too!
“Picture Courtesy of Ron Webber, Pro-Coat Systems, Orange CA”
Scuppers are a big problem area if not properly installed and caulked.
The scupper must be flashed on the inside and outside as well.
“Picture Courtesy of Ron Webber, Pro-Coat Systems, Orange CA”