Driveway Drainage: Slope Before Surface

Quick answer

Start with the existing condition and the outcome you want. A useful scope should explain what will be changed, what will stay, what assumptions are being made and how related problems will be handled. Surface water needs an intentional path. Low spots can create ice, algae and nuisance pooling.

What to check before you make a decision

The best starting point is a clear picture of the existing condition. These are the details most likely to affect the recommendation for this particular project:

• Surface water needs an intentional path.Moisture and drainage problems are rarely just cosmetic; the important questions are where the water is coming from, where it is supposed to go and whether nearby materials have already been affected.
• Low spots can create ice, algae and nuisance pooling.This detail should be discussed before the quote is finalized because it can affect the work method, materials, schedule or what is included in the contractor's price.
• Garage thresholds require careful grading.Sizing and layout affect performance after the work is finished, so measurements and site conditions should be confirmed before equipment or materials are finalized.
• Drains need a suitable outlet.Moisture and drainage problems are rarely just cosmetic; the important questions are where the water is coming from, where it is supposed to go and whether nearby materials have already been affected.
• Neighbouring grades and retaining walls can affect water movement.Moisture and drainage problems are rarely just cosmetic; the important questions are where the water is coming from, where it is supposed to go and whether nearby materials have already been affected.

Write down what you can observe safely and take a few photos. That gives the contractor a better starting point, but it does not replace an on-site assessment when the cause or condition is uncertain.

What can change the scope or quote?

Two homes asking for the same type of work can end up with very different scopes. The quote should make the main assumptions visible instead of hiding them inside one total.

• Excavation and base preparation. This detail should be discussed before the quote is finalized because it can affect the work method, materials, schedule or what is included in the contractor's price.
• Concrete/paver thickness and reinforcement. This detail should be discussed before the quote is finalized because it can affect the work method, materials, schedule or what is included in the contractor's price.
• Drainage and slope. Moisture and drainage problems are rarely just cosmetic; the important questions are where the water is coming from, where it is supposed to go and whether nearby materials have already been affected.
• Site access for equipment and materials. Compare the choice by suitability, installation requirements, maintenance and expected performance rather than by the product name alone.
• Demolition, disposal and finishing. Compare the choice by suitability, installation requirements, maintenance and expected performance rather than by the product name alone.

If any of those items cannot be confirmed until demolition or closer inspection, ask how the contractor handles discoveries and change orders. A clear process is more useful than a suspiciously precise number based on incomplete information.

Lower Mainland considerations

Drainage, base preparation and water movement are especially important for driveways, patios and walkways in the Lower Mainland. Drainage and base preparation are critical in a wet climate. Surface water, poor slope and weak base material can undermine even an attractive new driveway, patio or walkway.

Property type matters too. Detached homes, townhomes and condos can have different access, common-property boundaries and approval requirements. Before hiring, confirm which parts of the project are the homeowner's responsibility and whether any building or strata rules affect the work.

When it makes sense to bring in a contractor

A homeowner can usually gather photos, note when the problem occurs, write down measurements that are easy to take safely and list the outcome they want. The diagnosis and technical scope are different. Large cracks, trip hazards, settlement near a foundation or work involving significant excavation should be assessed before a new surface is placed. A good concrete and paving contractor should be able to explain what they observed, what they recommend and what would make the scope change after work begins.

Questions to ask before hiring

You do not need to interview a contractor with a huge checklist. A few project-specific questions will tell you whether the scope is thought through:

• How will the base be prepared?
• Where will surface water drain?
• What thickness/reinforcement is proposed?
• How are control joints or edges handled?
• What curing or use restrictions should I expect?

Listen for clear explanations. A contractor should be able to tell you what they know now, what still needs to be inspected and what is not included.

How to compare quotes without looking only at the total

Put the quotes side by side and compare the scope line by line. Check preparation, materials or equipment, related repairs, protection of the home, disposal, cleanup, exclusions, payment schedule, change-order process and warranty terms. If one quote is much lower, identify what is different before assuming it is a bargain.

For this project, pay particular attention to the items listed above under what can change the scope. Those are the details most likely to make two apparently similar quotes cover different work.

Frequently asked questions