Retaining wall cost to remedy backyard slope?

That would be a great way to flood your basement. Water should run away from the house and thats why the lawn is graded this way.

20k

Jerico wrote: ↑ That would be a great way to flood your basement. Water should run away from the house and thats why the lawn is graded this way.

OP probably meant to level it relatively flat and not completely flat. You don’t need a 33% grading to prevent flooding.

Jon Lai wrote: ↑ OP probably meant to level it relatively flat and not completely flat. You don’t need a 33% grading to prevent flooding.

Looks like the 33% is the swale and most of the yard is graded 4-5%

In our city there is a flood-plain regulation that for all new home construction, the ground floor must be above the level of the crown of the nearest road. This is supposedly to allow the city drainage system to work properly and prevent home flooding.

Most contractors are solving this by dumping in fill to raise the level of the property to the required height. If space is tight they may have to build a retaining wall around the property to do this, but I'm sure they would just leave a slope if they have the space to get away with it. Maybe this is the case with the OP's property.

Unfortunately this regulation was not well thought out, because many roads were already raised a meter above the surrounding land when they were originally built to assist in water runoff and snow clearing. So now in theory the regulation calls for the entire city to be raised by one meter via landfill one property at a time. In the meantime areas of new infill home construction are dotted with houses sitting in one-meter-high trays raising them above the level of surrounding houses and causing flooding on those properties.

Thanks for your input. I think my case is different though, because there're surrounding properties on the North, West and East. The road is on the South.

The house itself would be sitting on a higher ground than the other properties already (except the ones on the West towards the hilltop).

I'm now thinking about maybe asking the builder to change the grading so that the slope concaves towards the house.

In this way, I can build a deck to "cover up" most of the slope. Not sure how this impacts water drainage though.

fiddlewin wrote: ↑ I'm now thinking about maybe asking the builder to change the grading so that the slope concaves towards the house.

In this way, I can build a deck to "cover up" most of the slope. Not sure how this impacts water drainage though.

Concave
Toward the house ...

Never gonna happen
The slope has to go AWAY from the house, so the water runs off / away from your foundation
So slope will run highest to lowest front to back
(Most common ... and if in a subdivision, usually done cuz the back of the lot has an easement for drainage / storm sewar)

Occasionally, the slope will run side to side...
but it’s rare
Cuz usually a property has close neighbours / houses ... where your run off would just be affecting their home’s foundation

Honestly, you cannot eff around too much with the slope / grade on your property
It’s designed this way for a reason
And cuz it is a flood hazard the municipality is going to uphold that design
(It’s designed like this for the whole of a subdivision / municipality ... to compensate for all the non organic surfaces that happen in a community ... drainage is a serious matter ... so it’s not just your house, it relates to a far greater whole)

By "concave" I mean looking from top-down. It's just the "L" in the plot would be folded along the diagonal of the yard.

In this way, the house would still be on the high spot with the slope decling away from it. It's just the slope would be moved closer to the base, and will be covered by a future deck - similar to a look-out yard.

fiddlewin wrote: ↑ By "concave" I mean looking from top-down. It's just the "L" in the plot would be folded along the diagonal of the yard.

In this way, the house would still be on the high spot with the slope decling away from it. It's just the slope would be moved closer to the base, and will be covered by a future deck - similar to a look-out yard.

I assume you mean you want it to look like this

----|
----\
------____________

Instead of

----___
----_______\
----________|

Jon Lai wrote: ↑ I assume you mean you want it to look like this

----|
----\
------____________

Instead of

----___
----_______\
----________|

When water fills his neighbours basement he can go like this:

¯\_(ツ)_/¯

Water will flow to the neighbouring properties anyway since they're lower.

Just an idea, since the road is on the south side maybe a horseshoe grading will work? so the water run on the sides of the house and to the road (sewers).

There would be other properties on the West and East. West property is higher - so basically this house is on the "corner" of a small hill, which creates this "L" shape.