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fordmexico

Mar 14, 2014, 11:13 AM

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Repair Cracks in Outside Walls

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We have several diagonal, hairline cracks in the walls surrounding our jardin. I have received numerous recommendations on how to repair them - epoxy, silicon, mortar, cement and various combinations of them.

Does anyone have any success with or lack thereof of any of these methods or perhaps other suggestions?

The engineer who supervised the building of the home for the previous owner does not believe them to be structural but cannot give a definite cause for them. Since of home was built on a hillside, settling is the most likely cause. The walls of the home, itself show no signs of cracks.



Grevo


Mar 15, 2014, 8:50 PM

Post #2 of 7 (20282 views)

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Re: [fordmexico] Repair Cracks in Outside Walls

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The diagonal crack is likely the result of differential settlement of the wall. This is a phenomenon where the one section of the wall settles (moves downward) faster than the adjacent section of the wall. The reverse situation can happen as well where one section of the wall is pushed upwards due to various reasons (i.e. tree roots, expansive soil conditions, etc). The diagonal crack is due to the relief of shear stress between the adjacent sections. Hence it is typically a structural issue. I found this good article describing diagonal cracks.
http://www.buildingdoctor.com/subsidence/
You can “repoint” the joints in the wall with various materials depending on the width of the cracks and the type of movement, however, this could become a repetitive process of the crack opening, if the root of the problem is not discovered. Cracks can be monitored using various methods to determine if they continue to be active (continue to open) or conclude the cracks have stopped and settlement (or uplift) has stopped and was a one-time event. The repointing of the joint yes, can be done using various materials however, it is very dependent on the scale or size of the crack, its activity and the desire as to how to hide the repair.

Not sure the other (builder) engineer’s response is very conclusive or thorough, but thank goodness the cracks are in the outside walls and not the walls of the house itself.
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Sin Compentencia tenamos Incompentencia!


AlanMexicali


Mar 16, 2014, 5:01 AM

Post #3 of 7 (20269 views)

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Re: [fordmexico] Repair Cracks in Outside Walls

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We have several diagonal, hairline cracks in the walls surrounding our jardin. I have received numerous recommendations on how to repair them - epoxy, silicon, mortar, cement and various combinations of them.

Does anyone have any success with or lack thereof of any of these methods or perhaps other suggestions?

The engineer who supervised the building of the home for the previous owner does not believe them to be structural but cannot give a definite cause for them. Since of home was built on a hillside, settling is the most likely cause. The walls of the home, itself show no signs of cracks.


Are the walls constructed of cement block and plastered [mostly hollow or filled with cement and some vertical and on all rows horizontal rebar?] or brick and plastered with cement and rebar posts and top cap?

If brick I had 10 cracks in my house in Mexicali when the big 7.2 earthquake of 2010 hit. I looked at several ways to get the hairline and a couple of 1/4 inch cracks repaired and a few were diagonal. Most where along seams where the doors and windows met going up to the ceiling.

In the end my buddy, an abañile, trenched about an inch on each side not very deep and used cement adhesive called here cement glue. It is a white powder and has epoxies and I have never seen a crack show and there has been other earthquakes since [not near 7.2] so if they were weak they would have opened up, I presume. Very stong stuff.

This website is from Spain but is the same stuff available in Mexico.


http://www.depinturas.com/Mortero-tricomponente-Sikaguard-720-EpoCem.html&osCsid=dg4ub50jojn1dvbkl8dsuh1ps3


Google translation:

"Sikaguard ® - 720 EpoCem ®

Sikaguard-720 EpoCem is a thixotropic mortar of three components, with cement, resin, and modified epoxy, of fine texture for levelling and finishing surfaces of stone, concrete or mortar.

Usage:

As a levelling layer on concrete or mortar, in thicknesses of 0, 5-3 mm, on horizontal or vertical surfaces in new works or repair, in aggressive chemical environments.

As a temporary barrier of moisture (TMB) (min. layer thickness 2 mm) under layers of resin epoxy, polyurethane and PMMA *, when the stand has a high moisture content or placed on fresh concrete.

As sealer pores for the re-profiling and leveling of concrete surfaces.

In food industry, as a layer of re-profiling on walls and medium rods, before applying a coating suitable resin epoxy or polyurethane.

Suitable for humidity Control (method of the according 1504-9 2.3 principle 2).

Suitable for repairs of concrete (principle 3, 3.1 and 3.3 of the UNE-EN 1504-9 method).

Suitable for the physical resistance (method 5.1 of EN 1504-9 principle 5).

Suitable for increasing the resistivity (method 8.3 of EN 1504-9 principle 8).

To see notes of application/limitations.

Features:

Excellent protection of the concrete in aggressive environments.

Good chemical resistance.

Easy and fast to apply.

Class R4 of the UNE-EN 1504-3.
Impervious to liquids and permeable to water vapor.

Excellent adhesion to concrete, wet or dry.

Minimum waiting time before applying other Sika finish resins.

Ideal for fine surface preparation.

For internal and external use.

It contains no solvents.

It can be applied by projection."


(This post was edited by AlanMexicali on Mar 16, 2014, 5:42 AM)


fordmexico

Mar 22, 2014, 1:00 PM

Post #4 of 7 (20145 views)

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Re: [fordmexico] Repair Cracks in Outside Walls

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Thanks to all for your suggestions.


Stuart A. Frisina

Jun 27, 2014, 12:46 AM

Post #5 of 7 (19157 views)

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Re: [fordmexico] Repair Cracks in Outside Walls

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Fixing the cracks is not a easy work because it requires too much clarity. I think you should hire some restorer for fix the cracks. If you are thinking to do at yourself then its not a good idea. A stone and marble restorer is much experienced then your ideas.


CozICan

Jun 27, 2014, 6:36 AM

Post #6 of 7 (19147 views)

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Re: [fordmexico] Repair Cracks in Outside Walls

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If they are only hairline cracks in the stucco coating of the wall I have had success with a Comex product called OK resanador. It is a lightweight filler than can even been used on ceilings. For small cracks I usually put a little bit on my finger and force it into the crack. For larger cracks you will want to use a narrow spatula. With a light sanding afterwords you will have trouble finding the crack later. I have used it in many places around my house in the past 7 years and have always been satisfied. This is a translation from Comex's website :

OK resanador

Filler and lightweight acrylic mix, ready to apply indoors and outdoors.

It is suitable for spackling holes, cracks, holes in concrete surfaces, plaster, wood and flattened.

Good luck with your repairs

CozICan


rvgringo

Jun 27, 2014, 9:33 AM

Post #7 of 7 (19127 views)

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Re: [CozICan] Repair Cracks in Outside Walls

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The most common fix is with cemento blanco, available at any hardware, paint or masonry supply place. It is cheap and dries fast, so mix just a little with water and brush it into the crack. Using a spatula may leave a too smooth/shiny texture if your surface is textured. No sanding should be necessary. It dries white and may be painted the next day.
 
 
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