A French drain keeps your foundation dry by evacuating water that accumulates around your home. Its lifespan varies, as does its installation or replacement cost, due to several factors. We’ve put together an article to explain which factors should be considered when costing out a French drain installation or replacement.
The cost of replacing a French drain
The price of a French drain replacement usually ranges from $15,500 to $25,500, including the waterproofing membrane for a typical bungalow. Usually, it can cost anywhere between $100 and $200 per linear foot – all depending on obstacles present. However, it can also vary depending on the factors present throughout the installation process:
- Installing the waterproofing membrane on the foundation;
- Installing the French drain;
- Installing the backfill;
- Cleaning the premises
Note: the pricing mentioned above is averaged out for both Greater Montreal and Greater Toronto, and includes all renovation stages.
Looking to get a price estimate for your French drain replacement?
At RenoAssistance, we have handled hundreds of French drain projects, so we can easily evaluate the cost of installing or replacing yours by taking a look at some photos and discussing the details with you. We can easily access past contractor quotes to be able to provide you with a fair idea of the cost of your project.
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What factors affect the cost of a French drain installation?
The cost of your French drain’s installation can vary depending on many factors, such as:
- How long it takes to install it (in regards to complexity)
- Its distance from the sewer
- The type of soil (rock, clay, etc.)
- If there are cracks to repair in the foundation before moving forward
- Having to waterproof the foundation (if not already done)
- Ease of access (are there obstacles complicating excavation?)
The factors mentioned above are only some that should be considered during a French drain’s installation. For instance, when talking about accessibility, how easy will it be to get under the covering surface? Is there asphalt or concrete to break down? Is there a garden that will need to be dismantled? What needs to be done? Also, space constraints will play a big role in the cost of installing your french drain. How much space is there between your home and your neighbour’s? Will smaller (and typically more costly) equipment be needed for the job? Of course, our Renovation Advisors will be able to help, but it’ll be our 360° Verified Contractors that’ll be the experts in the matter.
In the province of Quebec, the cost of the work should be similar from one region to another. However, in Montreal, prices tend to be slightly higher by about 5%, and prices can be expected to be about 15% higher in Ontario, particularly in urban areas such as Toronto and Ottawa.
Is a French drain still necessary?
All new houses are equipped with a drain, but it’s not always necessary (note: it might be mandatory, depending on where you live). If the groundwater doesn’t reach the foundation during flooding periods, there shouldn’t be any complications. However, changes to your lot (new construction, pool, levelling, etc.) can quickly change the situation and require you to install a French drain. If you notice a high humidity in your home or water seeping through the concrete slab, it is essential to install a drain to avoid significant damage.
Note that before the 1970s, French drains weren’t mandatory in many areas of the country. Therefore, it’s quite possible that, if your house dates from before the 70s, it is not equipped with a French drain and that the water infiltrates more easily into your basement!
"I'm here to help you with your french drain project"
- Jonathan / Renovation Advisor at RenoAssistance
Why does French drain replacement cost more in town?
The most common issue contractors face when installing French drains in town is ease of access. Neighbours or street furniture might be so close that it’s impossible to excavate with regular sized equipment. Parking problems and other challenges related to excavation machine access will influence the cost of a French drain – as it lengthens the time required to complete the project.
How do I know if I need to replace my French drain?
When you repeatedly find cracks in your foundation, there’s a high level of humidity in your home during rainy seasons, or when there is rain water build up on your property. These are all tell-tale signs that it might be time to replace your French drain. They indicate that your French drain is most likely no longer working properly.
How can I save on my French drain replacement?
It’s possible to save a few dollars by facilitating contractors’ access. You can, for instance, remove elements that are found near your house, such as a wooden balcony, a fence, shrubs, flagstones and all accessories like a barbecue, tables, chairs, etc. that are in the way. Another cost saving tip is to opt for a less expensive type of waterproofing membrane. However, in this case, it’s important you weigh the pros and cons before deciding on the kind of membrane in order to ensure its effectiveness on the long-run. You won’t want to have to go through this entire process all over again a few years down the road simply to save money short-term; it’ll end up costing you twice as much if the chosen membrane isn’t effective.
What is a French drain replacement made of?
The drain is a perforated pipe surrounded by 0 to 3/4 inch crushed stone. It has a geotextile membrane. When installing a drain, the foundations also receive a waterproofing membrane.
Should I replace my waterproof membrane too?
If it’s fairly old, seems dried out or your contractor advises you to replace it, you should. Once excavation is done, the membrane becomes easily accessible and it will not cost you much more to replace it. The additional costs will only encompass the necessary equipment and additional labour for this part of the project. Seeing as the most expensive part of a French drain replacement is the excavation process, it won’t be much more. Regardless, in the long run, it’ll be well worth it. You’re sure to not have any water infiltration issues for a while.
Maintain and replace your drain for long-term savings
A French drain is a long-term investment: it has a lifespan of between 25 and 40 years. Also, contractors usually offer warranties against infiltration due to the drain’s malfunction. So, be sure to ask them about it before signing a contract. You’re always better off being safe than sorry.
However, it’ advisable to have the drain cleaned and inspected every 5 to 10 years regardless. A drain in clay soil, or containing a lot of sand, will require more frequent maintenance. Soils with high iron content, on the other hand, can cause iron ocher issues. Frequent checks can essentially avoid a lot of problems.
Many homeowners aren’t even aware their home is equipped with a French drain as it isn’t easily accessible or necessarily visible. To ease its maintenance, it’s possible to verify its condition by camera inspection. An expert assesses your terrain and inserts a high definition camera directly into the vertical drain that comes out of the ground to assess its condition.
Installing a French drain is a complex process that depends on various factors. We’d be glad to have one of our Renovation Advisors refer you up to three 360° Verified contractors that specialize in French drain replacement. They’ll each provide you with quotes and we’ll help you understand which contractor best fits your needs.
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