Foundation Wall Cracks - Xypex, Blue Tar & Membrane 1

[bobrob1892]

I am in the process of replacing the original french drains around 3 walls of a 30 year old home in Southern Ontario. There is a serious water seepage problem through the concrete block walls in the basement but not through the basement slab. A 7' deep, 3' wide and 40' total length trench (~10 foot sections) has been dug to reach just below the foundation footing, and the walls have been shored. The old clay tiles are in fair shape but I plan to replace them with 4" geo-fabric covered perforated pipe. I have several question which require your expertise.

1. Originally the concrete block walls were parged with cement and sealed with a very thin layer of tar. The walls have been washed and metal brushed. There are horizontal cracks at the mortar joints in 4' lengths no larger than 1/8". Thera are a couple of vertical cracks along the mortar joints and right through the blocks about 6' long and 3/16" wide. What is the best method of sealing these cracks?

My thought is to use hydraulic cement on the vertical cracks, then apply two coats of Xypex Concentrate waterproofing material, cover the wall with "Blue tar", then place an uninterrupted sheet of waterproofing dimpled membrane without the nails over everything, and then backfill.

2. Where the cement blocks meet the foundation, there seems to be gaps allowing water to seep in. The parging cement partially covers these areas but it is fractured mostly. How would I go about sealing this area without taking out the old cement work?

Your response is greatly appreciated.

Bob

 

[dik]

The use of perf pipe and a sock for replacing the perimeter tile is good. This should be connected to a sump or free drainage (prevented from freezing).

The horizontal cracks in the mortar joints is a bit of a concern. If these have been caused by surcharge or lateral earth pressure or freezing it may be necessary to reinforce the wall from the inside by using vertical beams from the floor to the basement slab. I often use thin walled HSS tubing for this repair.

Rather than use a hydraulic patch, you might want to consider using a polysulphide or silicon caulk material that will permit movement. If by dimpled membrane, you are referring to Mirafi mirdrain or something similar and blue stuff, I'm not sure that the zypex is needed.

At the foundation, where the mortar 'wash' has deteriorated, this should be repaired and the dimpled drain wrapped down and over the foundation to catch the perimeter drainage tiles.

Dik