Poured concrete foundations versus block foundations

“I would never buy a house with a block basement.”
“Block basements are water problems waiting to happen.”


“Block foundations are a total turnoff.”

Buying a resale house is a momentous and sometimes stressful experience, and with most fi rst-time buyers lacking the knowledge to accurately gauge the physical condition of a home foundation, they rely on word of mouth, Google or advice from well-meaning family members.

In my experience showing houses and cabins in Kamsack, Madge Lake and the surrounding area to prospective buyers, the one question that comes up 100 per cent of the
time is whether the house has a block basement or a poured concrete foundation.

Without a doubt, if it’s block, they either mark that down on their notes as a negative or tell me they want to move on and not consider the house at all.

As I’m not an inspector or a contractor, I don’t have the construction training to intelligently discuss the intricacies of one over the other. What I do know is that there are listings
out there 20, 40, 50 years old with block basements and no evidence of cracks or water leakage. (To be fair, yes, some have cracks and water leakage as well.) This observation doesn’t mean much,however, without some scientific knowledge to back it up.

This is where respected building inspector Chris Herrington from Prairie Building Inspections in Yorkton comes in. His company provides not only professional inspections including roofing, exterior, structure, electrical, heating, cooling, insulation, plumbing, and the interior, as well as thermal imaging, which can detect moisture, electrical system hot spots, insufficient insulation, heating, air conditioning and duct system, structural issues, plumbing leaks, and
block versus not hot-button issue.

Homebuyers’ idea that block basements are inferior is in their mind, says Chris. A little knowledge can be a dangerous thing and can cause new homebuyers to overlook the big picture.
There is nothing intrinsically wrong with concrete block foundations, he said. Bulging and cracks can occur in both, but when trouble occurs, poured concrete foundations are
the most problematic. In fact, the strength of concrete block is what makes it such a common material for commercial buildings.

Many contractors will agree that concrete block foundations are more expensive during initial construction. There’s the labour to lay the block, the expense of the extra steel reinforcement plus the cost of filling the blocks with the special concrete. However, when talking about resale homes, the real cost of deciding between block and poured is if and when there’s trouble.

Neither system is waterproof or bulge-proof. There’s an interesting article by Mike Holmes in which he said: “Think of your house as a boat, except instead of floating in water, it’s sort of floating in the soil that surrounds the basement.

That soil is fluid; it’s in motion, and it’s shifting and exerting pressure at all times on your foundation.”

Cracks and bulges occur for a variety of reasons over time. When conditions are very dry, soil will shrink as water evaporates out, which can allow foundations to settle and actually may cause the home to slowly sink.

When conditions are wet, water pressure once the water freezes in the winter will cause the soil around your foundation to put even more pressure on your foundation walls.

Cracks can also occur during backfilling around the house during construction. Equipment can hit the wall or the load can be dumped against an improperly supported wall. “Cracks in concrete blocks are easier to repair than poured concrete walls,” Chris Herrington advises. “In the event of a crack, it’s possible to remove the affected pieces and replace them. A poured concrete wall will not tolerate any movement.

If it cracks, you could be looking at lifting the house, pouring a new foundation…I tell clients to budget $100,000 for a proper repair.”

Three things for homebuyers to remember when evaluating a foundation:

· Concrete block foundations and poured concrete foundations are only as durable as the skill in which they were installed. If a contractor took a short cut and did not fi ll every block with mortar/concrete and steel reinforced rods, the integrity of the foundation will be compromised.

· Some cracks, especially if they’re small and are caused by concrete shrinking do not necessarily cause structural problems, but they can allow water or insects to get into your home so they should be dealt with.

· Don’t ignore any crack in any type of foundation. Call in a building inspector, a structural engineer or foundation specialist for a professional opinion on whether cracks are due to normal settling or point to structural damage. Making an offer on a house conditional on a home inspection is common and could save a homebuyer thousands of dollars in the long run

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