Humidity Mystery, Brick Patch | Ask TOH
On Ask This Old House
Tom discusses the conversations a homeowner and a contractor should have before starting a renovation project; Richard travels to Orlando to diagnose and repair an HVAC system that is creating way too much humidity; Mauro demonstrates the technique for using a paint sprayer; Mark travels to Denver to patch a hole in a brick wall.
How to Manage Renovation Expectations
Tom discusses the conversations a homeowner and a contractor should have before starting a renovation project.
How to Patch a Hole in a Brick Wall
Mark travels to Denver to patch a hole in a brick wall.
Where to find it?
For such a small repair, it may be a challenge to get a mason to fix the brick wall, so Mark suggests renting a few tools and tackling a project of this size on your own.
To find matching brick, take a picture, identify a nearby brick yard, and show someone there the picture. It’s likely they will recognize the brick and be able to give you the few that you need for little money. In this case, Mark went to Summit Brick Company and they were able to find what he needed.
Depending on the hole in the wall, it’s likely that surrounding bricks or mortar may need to be carefully removed. An angle grinder with a vacuum attachment can be rented from most home centers and should help keep the dust down. Mark used a 5” angle grinder with tuck pointing guard and a nine-gallon dust extractor with automatic cleaning, both manufactured by Bosch Tools.
For mortar, Mark used a Type N premixed mortar bag, which is manufactured by Quikrete.
All the other tools required for this project, including the trowel, masonry brush, and jointers, can all be found at home centers.
Expert assistance with this segment was provided by MJM Masonry.
How to Use a Paint Sprayer
Mauro demonstrates the technique for using a paint sprayer.
Where to find it
To demonstrate paint spraying techniques, Mauro used a Titan Impact 640 Skid Airless Paint Sprayer.
Expert assistance with this segment was provided by Mauro’s Painting.
How to Diagnose and Repair a Humid Air Conditioner
Richard travels to Orlando to diagnose and repair an HVAC system that is creating way too much humidity.
Where to find it?
When diagnosing a humid air conditioning system, Richard usually follows a series of steps based on the most common issue and works his way to more specific issues.
First, Richard checks the sizing of the equipment. Square footage alone isn’t enough to determine the appropriate size of a unit, since insulation, building materials, window openings, etc., can all also impact how much work a unit will need to do. He’s often found that units are oversized with the thought that “bigger is better”, but when that happens, the unit won’t stay on long enough to eliminate humidity. If the unit is the wrong size, it will need to be replaced.
The next thing Richard normally checks is thermostat setbacks. If the setback temperatures are too far apart during the day, the air conditioning system will have to work too hard to eliminate heat and humidity in the building, which would explain why the house feels humid. Keep setback temperatures to around five degrees difference to prevent the system from overworking.
If neither of these issues is causing the problem, it’s time to start digging into the specifics of the system. In this case, Richard found that a UV light was requiring a fan to be on all day. That fan was pushing the moisture collecting on the cold coil of the AC unit back into the building, causing the humidity.
To solve this issue, Richard removed the UV light and adjusted the fan so that it only turns on while the unit is in cooling mode. He also installed the Healthy Climate Solutions MERV 16 air filter, manufactured by Lennox to fight allergens and other contaminants in the home.