![]() If the specific requirements for use of the product as approved is followed there shouldn't be a problem. In the case of DekBlocks, use of girders is prohibited and decks can't be more than specific heights above grade. IMO, we need to recognize alternatives and not just toss them out because they are different from what we individually have been doing for years. The manufacturers have to go thru testing and documentation to get the ICBO approvals so that their products/systems can be approved by building departments. Many homes today are built using this system but there is very little in the codes that cover them. The same thing is true for Structural Insulated Panels. However, there are accepted engineering principle that can be applied and the number and type of shear fastenings can be determined in that way. There is nothing in the UBC that specifically addresses how to deal with seismic/wind resistance in this type of structure. If there is test data approved by ICBO then engineering analysis can be performed to determine what size member is acceptable. This would be like saying that you can't use a particular type or grade of lumber because it isn't specifically listed in the UBC tables. The fact is that a particular building department may be reluctant to look at such because the building official doesn't have the expertise to understand it but that doesn't mean they are right. The codes allow alternative structural systems when supported by accepted engineering analysis. I'm a registered California Architect and AFAIK the code in Redding is UBC/BOCA. Then if you need to do some modifications or repairs you can work on a relatively small module. ![]() If this deck had been on relatively level ground instead of being 8' above grade on the downhill side, I would have used the DekBlocks.īTW, it's pretty easy to build decks with this system in 8'x12' increments. If I had built this deck with Dek-Blocks I would have had to use a least 48 Dek Blocks but would not have had to have the 5 4x10x16' Girders. This means that the poured footing will support almost 6 times as much weight as a DekBlock and you would naturally use a different framing scheme - Footings / Posts / Girders / Joists.Īs an example, I built a 16 x 26 Deck with just 10 Concrete Piers 24" in diameter on ground that tested out at 3000 psf. In addition, such footings are typically about 2' square as opposed to about 10" square for the DekBlocks. Once you pour a footing, you must go below the frost line and rely on the footings to maintain their elevation regardless of surface soil heaving. This redistribution of load results in the entire deck essentially floating much like a floating dock does on water. If the ground moves up or down under one of the blocks, the rigidity of the joist will cause the load to be distributed in a greater or lesser degree to the soil beneath it. This means that a 12' 2圆 will be supported by at least 3 dek blocks and even an 8' 2圆 would have 3 DekBlocks supporting it. Each 2圆 joist requires a DekBlock every 5 feet. These blocks are intended to be used so that there is only about 8-12 sq. ![]() And anyone who uses them because some engineer said it was ok anyway is a fool.I don't know what your expertise is, but if you are going to use a poured footing then using DekBlocks is not only unnecessary, but it's unwise. Dek blocks aren't legal here unless they are used with a footer.
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