We get many questions about anchoring sheds to asphalt. Here are some of the common answers. Please contact us (1 (973) 669-8214) for clarifications or to discuss your own requirements.
The model of the anchor depends on the expected forces to be encountered, primarily wind intensity and the height of the shed. For 8' high, heavy wood construction sheds, we recommend the use of the SP12-38 anchors. For higher sheds, or sheds subject to winds of 60 miles per hour, we recommend the use of the SP18-716 anchors.
Attaching wooden 4x4 Beam:
Note that the anchors must be flush with the asphalt, and the wood beam sits on top of the anchors. Drill a 1/2" clearance hole in the 4x4 with a 2" recessed 1" bore so that the bolts will be shorter. The rule is that the bolt length is to be 0.5 - 1" longer than the length of the bolt above ground. So if you were to use a 4" long bolt above ground, its total length needs to be 5". If you recess the head by 2", the bolt can be only 3".
I prefer shorter bolts as they are better at withstanding sideways (shear) forces.
Space the anchors 2-3'. Make sure that there is an anchor in each of the corners, about 4" away for the edge of the wood. Verify that the 4x4 is lying flush against the head of the anchors. Any gap will cause the anchors to pull out as you tighten the bolts.
Always consult the latest version of our installation manual. You can download it here.