Monthly Archives: January 2016

Tile Tips

Someone in San Miguel asked about setting tile:

There are a few basic rules but the subsurface needs to be evaluated. If you have cracks in the cement floor/subsurface they should be “bridged” or patched with an anti-fracture membrane perhaps reinforced with mesh. These membranes are flexible and absorb some of the movement that caused the crack and can minimize or lessen the transfer of the crack up through the finish tile. In the U.S. we often use “expanded metal lath” which is harder to find here. This is nailed down to the base and a first layer of thin set is put down to form and completely new base on which you use more thin set and then tile. This could be “overkill” for your conditions.

Next the concrete base must be really clean and free from debris, dust and especially grease and oil. For most residential applications a professional tile setter will level the surface with a first coat of a multipurpose “thin set mortar” in the low areas then continue with the tile setting job with more thin set that is designed for your application (indoor?outdoor?what kind of tile etc). It is sticky because it can be used over plywood, cement etc. It will probably be portland cement based and have latex and other additives that fortify it and give it adhesive quality. The tile stores here sell decent products.

TIP: Some tile setters don’t dampen the bottom of the tile before installation and if it is porous tile, it sucks the moisture out of the thin set so fast that the adhesion and strength of the setting compound is adversely affected. The thin set will harden too quickly and not bond. Dense, high fire, machine-made tile doesn’t need much moisture if any.

There are other methods such as chipping little notches in the base material (cement or mortar) so that the next application of plaster or cement or in the case of tile, the setting compound/thin set will bond better because it “keys” into the base (a standard practice here). If you want to know how effective this is, just watch how easily the plaster comes off the wall when it is chipped off an aging wall to prepare it for a new coat of plaster. Often it isn’t well bonded. This could be more due to a dirty dusty surface than lack of bonding from the notches.

Good luck with your new floor, Ron

Why is my house acting like a refrigerator?

GE nor Mabe built your house!  But I have lived in two beautiful homes with boveda ceilings and nice architectural details and for at least two months of the year, I had to go outside to get warm. No fireplace or electric heater could warm it up. The minute I turned off the heat, the room returned quickly to refrigerator temperatures.

So what’s going on?

Mass. Homes in San Miguel are most often built with stone, tabique/bricks, adobe and concrete masonry of different types. A lot of mass with no exterior insulation. As the temperatures drop in the fall and winter the dense heat absorbing mass goes to work. Your body radiates its heat out and the walls, floors and ceilings suck it up. Just like cooling coils of your refrigerator. To make matters worse, the homes in our area are often built completely connected without airspace between houses so the mass just increases….it is insatiable. Anyone living next door or even two doors down from a remodel knows that the masses are connected without the sound deadening and insulating quality of air space. Who’s banging on our walls ?

Sun. The only savior is the sun or massive amounts of gas and electricity. In the Centro, the sun isn’t so easy to come by and if you have some south facing windows then you are probably huddled in front of one of them during the winter.

Rules for Buying a New Home. If you haven’t bought yet you can minimize the “refrigerator effect” by following a few simple rules. Ask your professional Realtor to show you houses on the north side of streets that run predominately east west. The top of maps are almost always north. Your house should face the bottom of the map if possible. The street creates a little distance so the house across the street, in front of the lower winter sun does not cast a shadow on your home.  This will make all the difference. Nothing can replace the San Miguel sun.

I live in a home in upper Independencia, it is on the north side of the street, it has south facing windows and doors, it is cold in the early morning winter and quickly warms up as the sun floods in through the windows. It is not a “solar” house but it has very straightforward no nonsense design features that make the house comfortable all year long. My new neighbor bought her home without thinking of any of these concerns but happily is on my side of the street. Her “gut” feeling when she saw the house may have told her about the southern light and the suns warmth she would get to enjoy. She got lucky but you don’t need luck. You have information which is better.

Okay….so you fell in love with a house that doesn’t follow my “rules” and will have some cold rooms. Now what do you do? See my upcoming blog on clerestories and getting the most out of what little sun you have.




Is Silicone Caulk The Best?

Many architects and builders, especially here in Mexico, are having a love affair with silicone caulk. They use it in many applications where it is not the best option. So why is it so commonly misused?

Try to buy something else and you find out why. Superior caulks like polyurethane and rubber butyl can be hard to find and you may have to order it and wait.

Just a few Pros and Cons

We could talk about caulk for months but let’s just remember a few things about a few types of caulk and that will suffice for the average homeowner.

Silicone (100%). It is clear or white and most are not paintable. It’s main advantages are its stretch and strength coefficients and it remains flexible for a very long time. If applied cleanly (see my “how to caulk neatly” blog) it has a low visual impact although it is shiny on flat surfaces like stucco or painted plaster.  It is a remarkable product in this regard. It’s weaknesses include low adhesion compared to polyurethane and rubber butyl and because of this water can get through it over time. If it has a biocide or is mildew resistant, it can be used in tub shower areas.

Polyurethane. Pros include strong adhesion, durable over time, comes in colors (mostly in the U.S.). Can be found sanded to match grouts in bathrooms (see also “siliconized acrylic”). I am a fan of this caulk and have used it in tough applications for many years. It does dry out just a little over 20 years and gets stiff in the tube if not used within a year or so.  But it adheres like construction adhesive which is a very good thing unless you have to remodel and tear something out that is held together with polyurethane.

Rubber Butyl. This is an awful product to use, very sticky, messy, black or brown….but oh my does it last….and stick….and flex (careful, some types shrink). This is the best performing product and that is why window manufacturers and automobile manufacturers use it. If you are worried about water infiltration (around pools, fountains, windows and doors) then rubber butyl may be the way to go. But can you find it? I will let you know where in another blog.

Acrylic/Latex. Mostly garbage. Sorry but it is a marginal product that has a few indoor uses to fill cracks before painting (“painter caulk”). Don’t use it in the bathroom  or outside no matter what DAP says. Mold resistant …..not in my opinion. It may be “siliconized” and this improves performance considerably and may make it a paintable caulk. But why ruin a good product like 100% silicone by adding a crap ingredient like latex?

That’s the basics of the four types of caulks.