Roof Deck Drainage and Waterproofing

ARTICLE:  Roof Deck Drainage Problems. Waterproofing a 2 Ply SBS Modified Bitumen Roof Balcony in Edmonton, Alberta.

Recommendations for Waterproofing Outdoor Decks Over Conditioned Living Space. Roof Deck Drainage and Waterproofing - Inspection and Repair of a Torch-On Flat Roof on Outdoor Balcony at Multi-Family Condominium. Customers regularly call on us to have roof assessments (inspections) completed. During a roof assessment our journeyman roofers assess the roofs condition. We assess the roof for preventative maintenance reasons as well as inspecting existing problems that the customer is pointing out. We then discuss different scopes of work fix the problems as well as potential materials and costs related to the repairs. One of the most common calls we get for inspections and repairs are rooftop decks, balconies and patios. The primary reason the failure rate on rooftop decks is so high is because of the original installation. It is common for incorrect membrane choice to be the reason. In other words, many people install an outdoor deck membrane that is intended only for an outdoor deck and not a membrane for over a heated living space. If your rooftop deck or balcony is over a heated living area you require a special membrane that is also intended for low slope roofing (as well as deck waterproofing) and is approved for use over a conditioned living space. Common products for this are Dura-Deck or DecTec, both of which are a PVC membrane that are suitable to be walked on (so they do not require a floating deck over top) and they manufacture membranes suitable for over a conditioned living space. We use DecTec extensively and have had great results with it. Or, also common is the installation of a membrane that won't hold up to the foot traffic associated with outdoor living areas. Other reasons include simple age, wear and tear, drainage and issues relating to penetrations or floating deck assemblies on top of the membrane. Visit our main website for more information on rooftop deck waterproofing. This particular inspection and subsequent repairs was more focused toward an aging membrane and the associated repairs that come with not properly maintaining the deck membrane and building envelope over the years. The drainage problems were causing significant damage to the exterior of the building. Below you will find the inspection report. May 20, 2015: Journeyman Superintendent Attends for Balcony Inspection. Roof Inspection Location: 10245 116 Street NW Edmonton Alberta. Roof Inspection Date: May 20, 2015. Roof Type: SBS 2 Ply Modified Bitumen Torch-On Membrane on Roof Balcony. Site Location Type: Multi-Family Condominium.

This customer is experiencing a problem with water getting in the roof system and it draining out on a low corner and destroying some exterior brick work. In the area of the leak there are 2 laps of the SBS modified bitumen that have come apart.

Roof Deck Drainage damaging exterior of building. Edmonton, Alberta.
Roof Deck Drainage damaging exterior of building.
SBS Torch ON Seam Pealing back
SBS Torch-On lap pealing back.
SBS Torch on roof, seconf lap starting to come apart
SBS Torch on roof, second lap starting to come apart.
 

Scope: To repair this, degranulate the area and apply new torch-on stripping in and around the corner to seal in properly. Man hours: To complete 3 - 6. Material needed: 1 roll of SBS modified cap membrane.

The customer  would also like a quote for the following scope: to fill 13 pitch pockets on the roof and also seal the voids around pitch pockets with some detail sealer.

Area that needs sealing
Area that needs sealing at gutter to wall area.
Pitch Pockets that need filling
Pitch pockets at deck railing post termination area that need filling.
More seams on the sbs torch on roof that need to be sealed
More seams on the SBS torch-on roof that need to be sealed.

Man hours to complete = 10. Material needed: 4 gallons of portable sealer. 1 box of IKO MS Detail.

More Reading:
http://www.jlconline.com/decks/waterproofing-a-rooftop-deck.aspx
https://www.grscanadainc.com/Rooftop_Deck_Waterproofing.html
https://www.grscanadainc.com/DecTec_Deck_Waterproofing.html
http://www.dec-tec.com/
https://www.pinterest.com/generalroofing/dectec-deck-and-rooftop-waterproofing/
File to be updated when repair reports come in to office.
< End of report >
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Athabasca DecTec Balcony Assessment, February 2015

Our client, located north of Edmonton, reached out to GRS to explore the option of installing DecTec Membrane on a balcony off the second floor of their building. Scope of Work: 1) Removal and disposal of existing roof assembly under the existing membrane that would interfere with new surface installation. 2) Removal/replace rotten sheathing (if any). 3) Mild increase to slope to encourage drainage. 4) Door openings may have to be customized to account for new slope. 5) Flashing may have to be re-done to accommodate new slope as well. 6) Deck railing removed and replaced to ensure safety. 7) Waterproofing of walls to allow for vertical installations. Ensures watertight fit. 8) Upon completion of 1-7 (as necessary), floating deck can then be installed to support viable systems (SBS Modified Torch, EPDM, TPO, or PVC), though DecTec does not require a floating deck to sit atop the membrane.   Proposed Solution DecTec bore GRS's recommendation for this project, as we employ all of the technicians typically required to see a successful installation. The client was simply looking for a quote for this type of project, which we were happy to provide.   Existing Decking: Pre-DecTec Installation 1 Pre-DecTec Installation 2 Pre-DecTec Installation 3 Pre-DecTec Installation 4 Pre-DecTec Installation 5 Pre-DecTec Installation 6     Until next time,         The Roofers at GRS CODE: 4510 Contact Us Call our 24 hour emergency roof repair at 1.780.424.7663. Mail to: 3428 99 Street NW Edmonton, Alberta T6E-5X5. We service all of Alberta including Edmonton, Stony Plain, Spruce Grove, Fort Saskatchewan, St Albert, Sherwood Park, Leduc, Nisku, Beaumont, Lac La Biche, Grande Prairie, High Level, Westlock, Slave Lake, Edson, Drayton Valley, Devon, Camrose, Wetaskiwin, Tofield, Lamont, Morinville, Vegreville, Tofield, Millet, Calmar, Evansburg, Redwater, Onaway, Viking, Athabasca, High Prairie, Valleyview, Fairview, Peace River, Whitecourt, Mayerthorpe and many more rural areas and towns.