Click this messge to hide it.
The usage varies with each site but typically around 15-20 levelling shims are required per square metre of decking.
We recommend our levelling shims if you plan to lay your decking joists on a base which is slightly uneven, for example an existing area of concrete or paving which may have settled unevenly over the years. The shims are used as required to ensure that the joists are correctly levelled. Levelling shims are not essential with a brand new base, which should be level anyway. For this reason levelling shims are a low cost optional extra.
Levelling shims are also beneficial with any concrete or paving base if your joists are timber. Even if the base is level, these impervious plastic shims can be used as spacers to ensure that the joists are not in direct contact with the ground. This allows rainwater to pass freely under the joists which ensures better drainage. It also helps to prolong the life of timber joists. These benefits do not extend to composite joists which are impervious to water anyway. Also, levelling shims are not needed with an eco-grid base which drains freely anyway.