Monday, September 22, 2014
East Hamptons - Preventing Swimming Pool Deck Frost Heave Damage
What is Frost Heave?
More precisely it should be called "freeze heave." When the wet soils become frozen, they expand. These expansive forces usually go horizontally and vertically.
If the soils are constrained (surrounded by immovable objects) by a building foundation, retaining wall or swimming pool, they will push against those structures. The weakest structure loses, and may experience structural distress.
Usually these forces push upward, causing the concrete pool decks to heave or buckle.
An Ounce of Prevention
Proper preparation of the materials that underlie the concrete is key in preventing frost heave.
Preventing the underlying soils from becoming saturated, prior to a hard freeze is key. Replacing the soils with drain rock, to a depth below the frost zone will greatly reduce soil saturation.
However, the water must be given a way to escape. Perforated drain pipes, sump wells and daylight drains can assist as well.
Preventing water from running off of the decks and into the surrounding planters or lawns will also eliminate a lot of the ground water. An 18-24 inch deep (or deeper) footing around the perimeter of the deck will also prevent irrigation water from seeping back under the pool decks.
Keep it Dry & Warm
Basically, the key is to keep the soils under the pool decks from becoming saturated. Dry soils will freeze, but will expand minimally.
Saturated soils will expand exponentially, causing cracked concrete (allowing water to seep under the slab), loose stone work and heaved pavement. Well drained soils or gravel will not retain water & thereby not expanding sufficiently to cause damage.
Some success has been achieved with the heating of slabs and insulating the underside of the slabs.
Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: firstname.lastname@example.org or 408-776-8220. Visit his website at: www.aquatictechnology.com.
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