Things to Look For // Excavation

Welcome to our new blog series titled “Things to Look For” where we will aim to focus on specific areas of building a home.

The average home buyer does not have the experience nor the education to know the best trade practices. This blog will be less of a ‘how to’ and more an opportunity for us to help people understand certain practices. By highlighting specific areas hopefully this will shed some light on the construction of a home. A more informed consumer can make for a smoother build process by eliminating a lot of questions. 

In our first edition we are going to start from the beginning with the excavation and backfill of the lot. In most jurisdictions home builders are required to have a geotechnical engineer examine the soil before building. Once the excavation is complete the engineer does soil and compaction tests to ensure that where the home is being placed is stable and will have limited ‘settling’. Settling is a natural thing for a home to do and is almost impossible to eliminate entirely. Settling can result in small drywall cracks, doors rubbing and grout to crack. By following the best practices during the excavation/backfill portion of the build these problems can be minor and easily fixed once the home has ‘settled’. 

There are 4 basic soil types used during the backfill of a home. Here in the Comox Valley, we like to use Hyland Precast Inc to acquire our structural soil products.

1) 10m or screened pit run

This material is a mixture of small aggregate, gravel and sand. It is used in areas where heavy loads will be placed. IE) Under driveways, garage slabs, basement/crawlspace skim coats, concrete walkways and secondary parking spots. When used it should be placed in 6” lifts and compacted with a 1000lb compacter in between every lift. 

2) ¾" drain rock

This material is used to cover your perimeter drain prior to backfill. The perimeter drain of a home is meant to wick water away from your foundation thus decreasing the likelihood of flooding and increasing the longevity of your home. By covering the perimeter drain with ¾" drain rock it insures that water can easily flow into this piping and away from the foundation. Best practice is to place 12” of drain rock around the perimeter drain then covering it in a landscaping fabric. The fabric allows moisture to go through but stops the soil sediment from falling through the drain rock and into your perimeter drain during backfill.

3) Sand

Sand is used to cover up any utilities that run from a designated spot on the property and into the home. By placing 12” of sand on top of any electrical conduit or plumbing services it eliminates the chance of rocks puncturing them during backfill. It also signals future operators that there are services below if/when future excavations happen on the property. Best practice is to place caution tape on top of the sand before continuing back fill. 

4) Top Soil

This is used at the last stage of back fill. It is a nutritional soil topping used for planting grass, plants and helps to absorb ground water. It is generally only a few inches deep. Black Gold Landscape Supply is a great place for top soil here in the Comox Valley.

Being aware of these 4 basic soil types and how/when they are used gives an idea of what to look for during this phase of construction. 

Thank you for reading this blog post and we hope that you found it to be both informative and helpful. If you have any questions or concerns please feel free to reach us here: info@candordevelopments.ca

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Excavating to undisturbed soil.

Excavating to undisturbed soil.

Drain rock with sand over utilities.

Drain rock with sand over utilities.

Finished grade.

Finished grade.