by Michael McBride
Is your Project Tested and does it Meet the New Building Codes? Why are we Discussing Wind?
With all that we’ve been through the last year, one thing is for sure: People are looking for more space and whenever possible, outdoor space. This has caused property owners and their design teams, no matter how big or small, to try and use every possible square foot of their property to maximize their lifestyles.
There are endless possibilities for adding space to properties, but none more than roof decks, balconies and “walkout” plaza spaces. However, by using these new spaces, it means having to meet new building codes and specifically one “tricky” element in all scopes with roofs, above grade decks, or plaza areas: wind uplift.
High wind readings does not mean you need a Lok-down system, and low wind uplift doesn’t mean you do not need a Lok-down system. The highest wind uplift is at corners of roofs with roof perimeters being the next highest areas. The field of the roof sees the lowest uplift forces from wind. Example: Corners will see 2.5 to 3.0 times the uplift force experienced in the field while perimeters will see 1.5 to 2.0 times the field.
Knowing the wind speed will not automatically give you the wind uplift pressures your deck will experience. A wind study will need to be done on the building and its surroundings. The wind study will give you the information needed to make an informed decision on what products to use on the roof deck.
A“Lok-Down Wind Uplift Resistance System” keeps rooftop decks safe from hurricane-condition wind speeds. The architect/designer has to comply with the International Building Code (IBC) for the building design.
- ANSI/SPRI RP-4 2013 (RP-4) is the wind design standard for ballasted single ply roofing systems, as the basis for designing aggregate and paver-ballasted single ply membrane systems.
- (RP-4) is based on ASCE 7-10, minimum design loads for buildings and other structures; limits the use of RP-4 compliant ballasted roofs to building 150 feet high and lower.
- IBC 2018’s section 1504.8 surface and ballast materials in hurricane-prone regions and table 1504.8 maximum allowable mean roof height permitted for a buildings with aggregate on the roof in areas outside a hurricane-prone region further limit aggregate usage based on a building’s mean roof height, nominal design wind speed (Vasd) and exposure category.
ANSI Spri RP 4 – New Codes
Pavers fall under Section 3.3.2: Paver #2 Ballast as a special “concrete pavers minimum 22 psf; or approved interlocking, beveled, doweled or contour fit; lightweight pavers (minimum 10 psf) when documented or demonstrated as equivalent.” Pavers weighing less than 22 psf must be fully adhered to the roof and not on pedestals.
Wausau Tile has completed independent test results on its new hidden Lok Down Paver system with Florida Product Approval- NOA (A Miami-Date Notice of Acceptance (NOA) is a local product approval to meet the code criteria in the High Velocity Hurricane Zone (HVHZ) as defined by the Florida Building Codes (FBC)).
Don’t limit yourself when it comes to roof top pavers. Wausau Tile’s Hidden Lok-Down is available with any of our H-Series or V-Series pavers, allowing you a full range of colors, textures, sizes and thicknesses to choose from to fit your business, university, hospitality or retail needs. With easy installation and all of the durability and strength that you’ve come to expect from Wausau Tile, our Hidden Lok-Down is the perfect choice for any roof plaza, parking garage, pitched surface or roof terrace.
Similar to our Lok-Down System, we have proven safety standards that help make the most of your rooftop spaces without limiting space or security. With a reduced visibility of the system for a more aesthetic paver installation, the Hidden Lok-Down System is designed to resist wind uplift in paver installations, tested to withstand -240 pounds of uplift pressure.
Michael McBride
Michael McBride is the New England architectural manager for Wausau Tile.
