Lot Grading & Final Grade Tips

Why are rough & final grade so important?

Water is essential to life, but it can also be one of the most destructive forces nature can throw at us. Rough & Final grades exists to help prevent water damage in buildings.

Water damage in a residential building generally occurs in several ways, one of which is overground flooding

Lot grading addresses overground flooding. It is the engineering and implementation of elevations, slopes, and swales, to manage surface water by directing it to a controlled drainage system.

Rough Grade & Final Grade Explained

The rough grade is the of shaping the ground (clay, in Edmonton) to prepare for the final grade. Important points on the lot are marked with survey stakes. The rough grade survey is done to ensure the lot meets the City's drainage plan.

The final grade complements the rough grade by finishing with topsoil or ground cover. This must also be done to meet key survey points on the lot. If the final grade conforms with the lot grading plan the result is that all surface water will freely flow away from the building to a controlled drainage system.

Final Grading Tips

Slope away from the house

It is important to remember that a minimum 10% slope is usually required within the first 2 meters of the building. This translates into at least 8" away from  the building within the first 6'6". This slope helps deal with the inevitability that your back-fill will settle.

The basement of your home was probably made by digging a deep hole in the clay, and then pouring concrete foundation. After the concrete cures, loose clay back-fills the void surrounding it. So if the final grade requirements for slope away from the house seems a bit drastic, think of how you be glad of it when the back-fill starts to settle.

NOTE: Don't forget about those tough to reach areas like under then deck. We have seen many well executed final grades fail because the slope under the deck was not adequate.

Continuous slope

The final grade stakes are generally placed when the rough grade survey is completed. It is important to make sure these remain undisturbed so the final grade can be accurately matched to the marks on them.

While it is critical that the height of the soil is within tolerance of the marked final grade, it is also important to remember the principle of continuous slope:

• Except in the case of a mid-yard high point, the swale on the property line should slope continuously without changing direction.

The overaching principle here is that if your yard is designed to drain from front to back, you have to make sure that there are no low spots where water can pool (even if your grade matches the lines on the final grade stakes).

One of the common tricks to ensure your slope is continuous is by using a string line. A string line can be stretched taught between two grade stakes. Provided there is no sag in the line,  you can use it as a guide to ensure your slope stays continuous. It is very easy to see low or high spots when you have the string line as a reference.

Free-draining ground cover

If you choose to complete your landscaping before getting your final grade surveyed, it is important to consider what constitutes free-draining. The final grade survey will verify the ground height, ignoring free draining material.

This means that if you are putting decorative rock on your side yard, and you have to come up 4" to meet your final grade, you must install 4" of topsoil or clay and then put your rock on top. The reason for this is that rock is free-draining, ie: water will not run on top of it, but it will fall through. If the surface below is too low you will end up with pooling, settling, and potentially water damage issues.

Happy Grading!

New Sod - Care Instructions

There is nothing like coming home from work to a new green lawn instead of a dry and dusty lot! One of the things we love about landscaping is seeing the look on your face at that instant.

A new lawn is great, but once the sod has been installed there is more to the story if you want to keep that green feeling and look. There are primarily just 3 steps:

1. Water
2. Don't Water
3. Mow

The most crucial time for new sod is the first few hours after it is laid. Where possible, we try to purchase and lay the sod all in the same day. In most cases, this means the sod was growing in a field mere hours before it is installed. Naturally, getting water to the new sod is crucial within the first few hours of being unrolled. Since we use Manderly Sod, we recommend that you follow their lawn-care instructions when watering your new lawn.

Basically it boils down to this 7 day schedule for the first week in the life of your new sod:

1. Water
2. Water
3. Water
4. Water
5. Don't Water
6. Don't Water
7. Mow then Water

Manderley suggests that starting in the third week you reduce watering to 25mm or 1inch of water per week, but what about the first couple of weeks? From our experience it is hard to over-water sod when it is first down. In fact, we'd rather see that excessive water than have it shrink and expose the seams.

As a rule of thumb we prefer that the first day of watering soaks the sod well enough that the soil underneath gets completely wet. To quickly check this, grab the corner of one of the pieces of sod and peel it back to see. Once the soil under the sod is nice and moist, it will stay that way for a long time, this will draw the roots down into the ground. One of the drawbacks of this initial period is how soft it makes the soil; so, we encourage you to tread lightly on fresh new sod by using plywood, or some other method of weight dispersal, so as not to leave unsightly and annoying depressions from walking on the soft lawn.

NOTE: Once you are satisfied that the soil beneath the sod is completely wet, there is no need to keep pulling the sod back to check, this will just prevent the roots from taking hold where you peel it back. Simply sticking to the schedule will ensure your success.

 A healthy and happy lawn doesn't require much more than water, don't water, mow; but it does require all these things. It would be good to understand that day five and six are also important steps in the process of creating your healthy lawn. In taking two days off, after the roots have just started to set, you are encouraging the roots to chase the water downward. This promotes deeper root growth and a healthier lawn.

Happy lawn care!