Load Bearing Shims

Shims for Stone Decks

If you need to fill small gaps or spaces between objects to provide stability, load bearing shims, which are thin, tapered wedges made of wood or plastic, are traditionally what is used. The real benefit of load bearing shims are how they can support and be adjusted to ensure a better fit or provide a level surface. As indicated in the name, load bearing shims are designed to support a particular load or weight. For this reason, ones manufactured from plastic, or similar materials such as rubber, are better as they are constructed to support a specified load. In comparison, wood ones rely on the composition of the wood used and the moisture content within the wood which does not allow for an exact load bearing capacity.

Given that nothing is ever perfect, load bearing shims are very useful when constructing a stone deck or patio. The products you are dealing with are not “Mil-Spec” designed to exact and precise tolerances. Load bearing shims not only help you to ensure everything is straight and aligned as you need it to be, but are capable of supporting the heavy loads of the stone you will be using. When your framing materials are a little less than perfect, load bearing shims are perfect for leveling paver or porcelain tile or ensuring your subfloor is perfectly flat.

Depending on what you are trying to accomplish you can install the load bearing shim and use the pressure of the materials being shimmed hold it in place. To hold it in place you can put a fastener such as a screw through it or use construction adhesive. As stated above, not only are plastic or rubber shims better at supporting an exact load, they will also not crack and split when a fastener is driven through as would happen with a wood shim. If construction adhesive is your preferred method of installation, note that wet or damp wood shims will not adhere.

Most tapered plastic or rubber shims on the market are scored at predetermined locations allowing you to break them off as needed at the required shimming space. You will need to score yourself and break off the excess if using wood. Also, wood shims can swell up or shrink and deteriorate over time as they are affected by moisture or other environmental conditions, whereas the plastic or rubber load bearing shims will not. One of the better load bearing shims on the market is the EZ-Shim. These are manufactured in the USA and have a load bearing capacity of 8000 lbs psi.

Another very useful option is round load bearing shims that can be easily snapped apart into quarters and stacked up as needed. Bison Innovative Products manufacture two such shims; the B11 is a 1/16″ flexible rubber shim, while the PS1 is a rigid 1/8″ shim. If you are trying to level larger stone pavers or porcelain tiles these types of load bearing shims are ideal. The ability to break round load bearing shims into halves or quarters is particularly useful when working on a rooftop deck using any of the pedestal systems on the market.

If you are working with a rooftop deck and using any of the pedestal systems on the market, the use of round shims that can be broken apart into halves or quarters is particularly useful.

In a perfect world all your construction materials would be straight and true, but we all know that is never the case. So, whether you are transforming your wood deck into a stone deck or building a new one, creating that beautiful maintenance-free rooftop patio or laying that stone deck patio, the use of a quality load bearing shim will save you time and aggravation, as well as ensure your project comes out straight, level and will last a lifetime.