Jul 22, 2009
We are currently repairing a brick paver raised patio that has experienced considerable settling over the past few years. The homeowner noticed some settling a few years ago but ignored the pavers and walls until this past winter resulted in considerable failure.
Upon tearing down the modular retaining walls that were used to raise the brick paver patio, we noticed that the installing contractor did not use a geotextile fabric behind the retaining walls to keep the base material from filtering out. Also, the base in the trench under the modular retaining wall blocks was not wrapped by filter fabric either. A key installation item that was missed by the installing brick paver contractor was the lack of landscape or grade build up on the outside of the the raised brick paver patio walls. It is crucial to bury rows of blocks or build up the soil to bury the bottom rows of block to help avoid any flushing of base under the walls. The result of the wall failure was due to erosion and shifting of the base. As the base begins to erode,flush, or shift, the corresponding bedding coarse & pavers shortly follow by shifting and sinking.
We reinstalled the modular blocks over a re compacted base wrapped in filter fabric. After stacking the retaining wall back to the proper height, a geotextile fabric was installed behind the wall prior to re compacting base. We will wet the base and compact behind the wall a few times to try and maximize the compaction so the base will not settle and the brick pavers will not move either.
I explained to the homeowner that it is very important to address any visible settling of their brick pavers or retaining walls as soon as possible. A $100-200 brick repair a couple of years ago would have saved them the $1,600 repair of brick pavers they have now! We had to reinstall the retaining walls and lift & reinstall over 50% of the paver patio.