Ways to pre­vent bricks from be­ing leaky

The Palm Beach Post - Residences - - Front Page -

Ques­tion: When a blow­ing rain lashes my brick-ve­neer home, wa­ter streams down over the in­side of my foun­da­tion in the base­ment. I thought brick was wa­ter­proof. What’s hap­pen­ing? Is there a way to min­i­mize or elim­i­nate the wa­ter from en­ter­ing my home? What could have been done to pre­vent this night­mare?

An­swer: A brick fa­cade of­fers no struc­tural sup­port. Un­for­tu­nately, the Three Lit­tle Pigs fa­ble has helped foster the per­cep­tion that brick homes are re­sis­tant to huff­ing and puff­ing. It’s pos­si­ble to build a brick ve­neer home that doesn’t al­low wa­ter in­side your home, but it re­quires a vast amount of at­ten­tion to de­tail.

Your brick is leak­ing be­cause of mi­cro­c­racks that ex­ist where the mor­tar touches the brick. The shorter ver­ti­cal mor­tar joints are much more sus­cep­ti­ble to wa­ter in­fil­tra­tion than the hor­i­zon­tal mor­tar joints.

Wa­ter leak­age is usu­ally not an is­sue in a gen­tle rain shower. The wind-driven rain that pelts the brick is where the is­sue mush­rooms. The pres­sure of the wind blast­ing the brick forces wa­ter into the mi­cro-cracks. Each suc­ces­sive rain­drop that crashes against the brick is like a minia­ture ham­mer that pounds the pre­vi­ous drop far­ther into the brick.

Soon wa­ter is stream­ing down the back­side of the brick where it’s less than an inch away from the wood fram­ing of your home! You can see why it’s im­per­a­tive to have a wa­ter­proof mem­brane cov­er­ing the wood fram­ing to pro­tect it from liq­uid wa­ter.

The wa­ter that flows to the bot­tom of the brick must be cap­tured by a flash­ing. This wa­ter needs to be redi­rected to the out­side of the house in a con­tin­u­ous path­way that’s im­mune from get­ting clogged by the mor­tar as the brick­lay­ers in­stall the brick.

Your best bet at min­i­miz­ing wa­ter in­fil­tra­tion at this point is to in­spect the brick for any large holes or crack where the mor­tar touches the brick. Re­pair those with new mor­tar that’s made us­ing hy­drated lime and fine sil­ica sand.

The sec­ond step is to ap­ply two coats of a silane/silox­ane sol­vent-based wa­ter re­pel­lent to the face of the brick. You need a helper to do this. The helper wears a back­pack leaf blower and blasts the wall with air as you spray on the wa­ter re­pel­lent. This air forces the liq­uid deep into the brick to help block wa­ter path­ways.

Tim Carter

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