Foundation Inspections During Home Inspection
Foundation Inspections are very important due to cost of repairing a poured concrete wall can be significant. The most common concern that home buyers have is about water leaking through their foundation. If there is a crack in the concrete foundation most people assume that will cause a “WETT BASEMENT”! This is simply not true. Concrete and other masonry building products are not water proof. If there is an issue with a “high water table” or if your really unlucky, an “Artesian Well” under your basement, then you will most likely experience times where water is going to enter your basement. Most homes have a Sump Pump which will be able to deal with any surface water around your homes foundation. If you have periods of time, such as spring, where sump pump is running a lot, you may want to consider a back up pump and battery back up for times when power may go out.
During the Home Inspection Process we do a detailed foundation inspection of your foundation looking for any visible problems. All foundations including concrete, masonry block, wood, rubble or ICF foundations. Most home owners today will choose to buy or build a home with a basement foundation too enjoy the added living and storage space.
Types of Foundation Inspections
Concrete Slab Foundations
Slab on grade foundation – concrete is simply poured onto the prepared soil. It’s poured thicker at the edges to form a footing. Re-bar is added for strength and wire mesh might be added to reduce risk of cracking. Slabs are typically anywhere from four to eight inches thick and are reinforced with steel rods and drainage pipes. Once the foundation’s prepared, the home is built directly on top of it. In Canada slab foundations are used where there maybe a high water table and because of its low cost.
Crawl Space Foundations
Foundation inspections are also required for crawl spaces. Crawl Spaces are typically anywhere from two to four feet in height and are typically constructed where there is a high water table. They are extremely popular in Senior Modular Home Parks where the homes are not taxed for having a basement . In trailer parks they are usually just high enough to access water and sewer connections and are typically surrounded on exterior by wood panels. Older crawl spaces will sometimes have a sump hole dug into dirt floor and pump any excess ground water away from home. Crawl spaces maybe heated or unheated depending on use of building. Cottages will typically have an unheated crawl space with a small heated area containing water pumps and tanks. Water supply line will typically be heated using a heat trace line.
Ontario Building Code Definitions 188.8.131.52. Crawl Spaces
(1) Where a crawl space exceeds 1 800 mm in height or is used for any occupancy or as a plenum in combustible construction or for the passage of flue pipes, it shall be considered as a basement in applying the requirements in Article 184.108.40.206.
Foundation Inspections on Rubble Foundations
The earliest type of foundation is a “Rubble Foundation”. These are typically found in Century Homes. A rubble foundation consists of loose stone or rubble which minimizes the use of concrete. Most rubble foundations leak water and most Century Homes have little trenches around exterior walls to drain water into sump hole. This was no issue in day gone by as nobody was building rec rooms or bedrooms in basement.
Poured Concrete Foundations
Poured concrete basement wall foundations are considerably stronger than masonry block foundations. Poured concrete walls have more lateral strength, enabling them to resist more pressure from the water and the soil from the outside. A poured concrete wall doesn’t have joints like a block wall making it easier to waterproof. Poured concrete walls will have a minimum thickness of 6 inches resting on a concrete footing that is a minimum of 6 inches or 1 1/2 times the length of footing projection from foundation wall, which ever is greater. Most builders will install metal frames for doors and windows prior to pouring concrete walls.
ICF Foundations ( Insulated Concrete Forms )
ICFs provide durability and insulation for below-grade walls. Constructing ICF foundations involves dry-stacking expanded polystyrene foam panels, or interlocking hollow extruded polystyrene foam, to a foundation’s length. The forms are reinforced and braced. Workers then pour concrete into the hollow form panels. ICF foundation construction is a fast and simple method of building below-grade walls. The curing environment of ICF walls can produce concrete with about double the compressive strength of conventional poured concrete wall. This systems provide a continuous insulation system with little of no thermal bridging.
Damage or problems with your foundation can be caused by type of soil, water leaks, and inadequate water drainage, which could lead to frost heaving. The first and most obvious sign of problems are cracks in floors, wall fissures and damaged brick mortar joints. Most homes will develop small cracks in the first 1 to 5 years following construction and are typically of no concern. Horizontal cracks are a sign of excessive water pressure and could lead to movement of your foundation causing drywall to tear. When this happens you may want to consult with a Structural Engineer.
Foundation settling can occur where one side of your building maybe sinking. This is a serious issue and the sooner you contact a foundation repair expert in for repairs the better. Interior or exterior foundation piers may have to be added to existing foundation to stabilize area and prevent further damage.
Foundation lifting can occur where your foundation moves in upward direction. This can be caused by expanding and contracting soil. Clay soil is known for expanding and gaining volume as it absorbs water. Concrete slab foundations can be affected by water from a plumbing leak which is causing soil under slab to expand. Any soil which is retaining water can cause frost heaving which can move any foundation footing or wall.
If you notice new cracks in your foundation, any horizontal cracks, step cracking in your exterior brick and sticking doors and windows, you should consult with a Foundation Expert to assess and remediate any issues which are the cause of movement.
For more information on Foundations call Roger Frost at 705-795-8255 or Email Roger
Pre-Delivery Inspections are a valuable tool to find out important information about your new home. Not only to document the homes deficiencies for your Tarion Warranty but to create a Base Point for any visual signs of foundation cracking or movement or walls or footings. When purchasing an older home a Professional Home Inspection can identify any visual signs of excessive foundation cracking or movement.