A soil report is the single most useful document you can hold before you pour, dig, or screw anything into the ground. It is a written summary from a licensed geotechnical engineer that describes exactly what sits under your property, how much weight that ground can carry, and how your home foundation should be built to stay put for decades. If you are planning a build, an addition, or a repair in Ontario, the soil report is what turns guesswork into engineering.

Most homeowners never see one until a bank, a municipality, or a contractor asks for it. By then the report feels like red tape. It is the opposite. Below is a guide to what is inside a soil report, how it saves you money, and when your project actually needs one.

What a Soil Report Actually Is

A soil report, also called a geotechnical report or a soils investigation, is produced after an engineering firm drills or bores test holes on your site and studies the samples in a lab. The ground you can see is only the top few centimetres. Underneath, soil changes with depth, and those hidden layers decide whether a foundation stays level or slowly tilts, cracks, and settles.

Ontario is a patchwork of soil conditions. The GTA sits largely on stiff clay and glacial till. The Ottawa Valley hides sensitive Leda clay, sometimes called quick clay, that can lose strength when disturbed. Cottage country near Muskoka drops onto bedrock in one spot and deep sand or organic muck a few metres away. A soil report reads that layer cake for your specific lot instead of assuming your neighbour’s soil is your soil.

Quick take

A soil report is a geotechnical engineer’s written verdict on what is under your property, how strong it is, and what your foundation needs to handle it safely. It replaces assumptions with tested numbers.

Row of soil sample tubes showing distinct clay and sand layers from a borehole — Each borehole sample shows how the ground changes with depth.

What is Inside a Soil Report

Reports vary in length, but almost every one covers the same core information. Once you know the headings, the document stops looking intimidating:

Borehole logs. A depth-by-depth record of each soil layer found in the test holes, so you can see where clay ends and sand or bedrock begins.
Soil classification. The type of each layer, such as clay, silt, sand, gravel, till, or organic material, plus how dense or soft it is.
Groundwater level. How high the water table sits, which drives drainage, waterproofing, and frost decisions.
Bearing capacity. How much load the soil can safely support, usually stated in kilopascals, at a given depth.
Frost and settlement notes. Frost penetration depth for your region and how much the ground may move over time.
Engineering recommendations. The part that matters most: what foundation type suits the site, and at what depth it should reach.

Did you know

The recommendations section often names specific foundation options, and deep foundations like helical piles show up frequently when the good soil sits well below the surface. If a report calls for reaching load-bearing strata several metres down, driving to that depth is exactly what a screw pile does without excavating the whole lot.

How a Soil Report Helps You

A soil report is not a box-ticking exercise. It changes three things that hit your wallet and your peace of mind directly.

It right-sizes your foundation. Without soil data, an engineer has to design conservatively and assume the worst, which usually means a bigger, pricier foundation than you need. With test results in hand, the design matches the actual ground, and you stop paying for capacity the site does not require.

It kills nasty surprises. Finding buried fill, a high water table, or soft clay on paper costs a few thousand dollars. Finding it after the concrete is poured, when the structure starts to settle, costs many times more and can mean tearing work out. A soil report moves the discovery to the cheapest possible moment.

It clears permits and financing. Many Ontario municipalities and most lenders want a geotechnical report for new builds, additions, and larger structures. Having one ready keeps your project from stalling at the building department counter.

Pro tip

Ask your engineer to comment specifically on deep foundation options in the report. A good geotechnical firm will note whether piles are suitable and to what depth, which lets your foundation contractor quote accurately from day one instead of guessing.

Card guide listing the six sections inside a soil report from borehole logs to recommendations — The six core sections every soil report should cover.

Geotechnical report overview

When You Need a Soil Report

Not every backyard project needs a full geotechnical investigation, but the line moves fast once size, load, or soil risk goes up. The table below is a general guide for Ontario projects, not a substitute for your municipality’s requirements.

Project type	Soil report usually needed?	Why
Small deck or shed	Sometimes	May be waived for light loads, but sensitive or filled soil can still trigger it
New single-family home	Yes	Lenders and most municipalities require it for the foundation design
Home addition or second storey	Usually	New loads must be verified against existing soil conditions
Building on a slope or near water	Yes	Stability, erosion, and groundwater risk demand testing
Commercial or industrial build	Yes	High loads and code review make it mandatory
Foundation repair on soft soil	Often	Confirms the cause of movement and the right fix depth

This table is general guidance for Ontario projects as of 2026. Whether a soil report is required, and how detailed it must be, depends on your municipality, your lender, and your site. Always confirm the requirement with your local building department and a licensed engineer before you budget or build.

Save your money

If you are drilling boreholes anyway, ask the geotechnical firm to test at the exact spots your foundation will land. Extra holes are cheap during mobilization and expensive as a separate return visit, so plan the whole investigation before the drill rig leaves your Toronto or GTA lot.

Engineer reviewing a printed geotechnical report and site plan before foundation work — The recommendations section guides the entire foundation plan.

How to Read Your Soil Report

The steps below help you understand a soil report so you can ask better questions. They are not engineering advice. Only a licensed professional engineer can interpret geotechnical data for design decisions. DiamondTech Piles is not responsible for outcomes from actions taken based on this article. Always have your report reviewed by a qualified engineer for your specific project.

Start with the summary and recommendations. Most reports put the conclusions up front. Read what foundation type and depth the engineer recommends before anything else.
Find the bearing capacity and the depth it applies to. This tells you how strong the good soil is and how far down it sits.
Check the groundwater level. A high water table changes drainage, waterproofing, and frost detailing for your foundation.
Scan the borehole logs for soft or organic layers. Peat, loose fill, or soft clay near the surface are the layers that cause settlement.
Note the frost depth for your region. Your foundation has to reach below it so seasonal freezing cannot heave it.
Bring the report to your foundation contractor early. A pile installer can read the recommended depth and load and give you a firm plan instead of an estimate.

Download the free quick guide

A one-page checklist to help you read your soil report and ask your engineer the right questions.

Download the free soil report checklist (PDF)

Frequently Asked Questions

What is a soil report and who prepares it?+

A soil report, also called a geotechnical report, is a written analysis of the ground under your property. A licensed geotechnical engineering firm drills test holes, studies the soil samples in a lab, and documents the soil layers, groundwater level, bearing capacity, and foundation recommendations. Only a licensed engineer can prepare and stamp one. It is the document your builder, your municipality, and often your lender rely on to confirm that a foundation is designed for the actual conditions on your site rather than an assumption.

How much does a soil report cost in Ontario?+

For a typical residential project, a geotechnical investigation often runs from roughly $2,000 to $6,000, depending on how many boreholes are needed, how deep they go, site access, and lab work. Larger commercial or industrial sites cost more because they need more testing. It sounds like a lot until you compare it to the cost of fixing a settling foundation, which can run into the tens of thousands. Treat the report as cheap insurance and get a written quote from the engineering firm before work starts.

Do I always need a soil report to build?+

Not always. Very light structures like small decks or sheds may not require one, and rules vary by municipality. New homes, additions, buildings on slopes or near water, and any commercial project almost always need a soil report, and lenders frequently require it too. The safest move is to ask your local building department and your engineer early, because finding out you need one after you have designed the project can cost you time and rework.

How does a soil report affect my foundation choice?+

The report tells the engineer how strong the soil is and how deep the good load-bearing ground sits. If solid soil is near the surface, a conventional footing may work. If it is buried under soft clay or fill, a deep foundation such as helical piles is often recommended because it reaches down to the strong layer without excavating the whole site. The recommendations section is where the report points directly at the foundation type that fits your ground.

How long is a soil report valid?+

The soil itself does not change quickly, so the physical data in a report stays relevant for years. What can change is the code, the project scope, or the site, for example if fill is added or nearby construction alters drainage. For most projects an existing report is fine if it covers the right area and depth for what you are building. When in doubt, have your engineer confirm whether an older report still applies or needs a supplementary investigation.

Have a soil report in hand and not sure what it means for your foundation? DiamondTech Piles reads geotechnical recommendations every week and turns them into a clear plan for steel piles in Toronto, the wider GTA, and Ontario. Get in touch for a free quote and we will tell you straight what your ground needs.

What Is a Soil Report and How Does It Help Me?