Soil Types and their Characteristics [Foundation Repair Tips]

Figure out what type of soil you have and why it’s important to understand at least 2 major characteristics that affect your home’s foundation.

Timestamps: Loam: 00:02:10, Sand: 00:02:28, Clay: 00:02:46, Silt: 00:02:59, Organic Deposits: 00:03:15, Mud: 00:03:29, Coastal Beach: 00:03:47, Tidal Marsh: 00:03:56, Drainage Class Excessively Drained: 00:04:58, Somewhat Excessively Drained: 00:05:07, Well Drained: 00:05:16, Moderately Well Drained: 00:05:22, Somewhat Poorly Drained: 00:05:33, Poorly Drained: 00:05:43, Very Poorly Drained: 00:05:56

The foundation supports the walls, the walls support the roof, and the soil holds them all. But how can you tell if the soil will be a good home for your house? You need to answer some important questions.

Is the soil stable, or does it have properties that can cause the foundation or walls to crack? Is the soil in an area subject to flooding? Will storm runoff drain safely away from the house and lot? Or will it turn a yard or basement into a pond? Does the soil have a high seasonal water table that can cause a basement to flood or a septic system to fail?

There are two important characteristics of soil that we need to look at. Soil is classified and divided into many sub-categories, but the ones we care about the most are soil type and soil drainage class.

Here is a list of the soils commonly found in New Jersey:

Loam: Contains 7-27% clay, 28-30% silt, and less than 50% sand. It’s said to be the ideal soil to build on because it handles moisture in a balanced way and doesn’t shift. (🐊 3 Ways your Soil is Causing Foundation Problems | Expansive Soil-–JMc)

Sand: There are different kinds of sand. Sand doesn’t retain water and doesn’t change in size with weather conditions, making it safe to build on. It’s best to build on sand that’s been compacted with other materials to make it more stable. Over time, sand can wash away and leave gaps underneath the foundation.

Clay: Is an expansive soil, meaning it expands when wet and it shrinks when dry. Because it changes size so much, it’s not good for foundations because it puts a lot of pressure on them.

Silt: Retains moisture longer than other soils. It’s cold, and drains poorly. Silty soil is expansive, which makes it bad for your foundation walls just like clay. It feels like flour when dry, and it’s smooth when wet.

Organic Deposits: They are a dark soil formed of decomposing organic material, also called peat. Peat is very porous and changes size depending on the weather like clay. It has a very low capacity to hold weight and is very bad for building on.

Muck: Is a sticky, soft and watery mixture also called mud. It has some organic materials and presents the same issues as organic deposits.

Coastal Beach: It should be no surprise that the main issue you’ll run into with coastal beach is pressure on your foundation from flooding.

Tidal Marsh: Is not totally dry and not totally liquid. Marshlands absorb water and slowly release it again like a natural sponge for the environment. Marshland is TERRIBLE to build on, even if it’s been filled with sand by developers. You’ll always have water and settling issues and water displaced by construction will either seep back into your basement or flood the houses downstream of you.

Soil Drainage Class: Refers to how often the soil is wet, and how much water it holds. This affects the amount of water pressure on your foundation walls.

Mottling: Mottled soil is irregularly marked with spots that differ in color and size. Usually indicates lack of drainage and poor aeration.

7 Soil Drainage Classes:

1) Excessively Drained: Very porous, low water capacity, no mottling

2) Somewhat Excessively Drained: Very permeable, not quite as porous, no mottling

3) Well Drained: Nearly free of mottling

4) Moderately Well Drained: Slowly permeable top layer, deeper layers have mottling

5) Somewhat Poorly Drained: Wet for significant periods but not all the time, sometimes there’s mottling 6-16 inches below the surface

6) Poorly Drained: Wet for long periods of time, light gray, may be mottled from the top down- not always

7: Very poorly Drained: Wet nearly all the time, dark gray or black surface layer, gray or light gray deeper layers, may or may not have mottling

This is only a rough estimate and onsite investigation should be done. Soil type tells you whether or not that soil is going to move, making your house unstable. Drainage class tells you how much water pressure your basement walls are under.

Your soil may contain a mixture of these properties, and your altitude also changes the soil’s behavior.

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🐊 MASSIVE Project at Life In Christ Ministries, Bridgeton NJ-

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