Bricks falling off chimney

Q.   Our home is 25 years old. We noticed pieces of brick falling onto the garage roof. We have had a waterproof liquid coating put on two times in the last year. It has now been recommended to rebuild the entire chimney (an expensive proposition). Is this the only way to correct this? What would be the harm in just leaving it? We see no leakage or any other observable problem.

Spalled Bricks
Spalled Bricks

A.    Spalling of brick surfaces is caused by moisture in the bricks that freezes before the bricks have had a chance to dry out. If the coating applied on your chimney is truly waterproof, it was a mistake to apply it. That simply prevented any moisture that had been in the bricks from drying out.

If this situation is not corrected, damage will continue and, eventually, the chimney will be beyond repair.

If the damage is not too advanced, a competent mason may be able to remove and replace the spalled bricks. But the cost of doing so may be close to, or exceed, the cost of total replacement. New bricks can receive a water-repellent coating, but not a waterproofing coating. Be sure it is siloxane-based.

Painting a brick fireplace wall

Q.    We have a brick fireplace wall 16 feet by 8 feet that was a pale beige when it was  installed by a previous owner. Years of wood burning, cigarette smoke, and cooking have turned it dark. Could it be painted? If so, what product should we use and would it have to be cleaned first? There is carpeting around it except for a small hearth. What kind of contractor should be hired for this type of job?

A.    The bricks can be painted but they will have to be cleaned first. Smoke, soot and cooking pollutants can be removed by scrubbing the bricks with a cleaner that contains bleach. You’ll have to tape plastic to the carpeting and cover the plastic with old towels to absorb any dripping solution. The bricks will have to be rinsed clean — another difficult exercise. The best contractor to get is a well-respected and experienced painter who will know what is the best paint to use.

Faces spalling (falling off) from decorative chimney bricks

Q.    Our 1-1/2 story frame house was built in about 1948. We have over the years corrected a number of deficiencies such as water in the cellar and poor attic ventilation, using techniques that you have suggested in your column. Our current problem started about 5 years ago. The chimney is built, or at least faced, with a red decorative brick, standard size with the face scored.

The faces of some of the bricks were spalling (falling off). We had a mason  suggest applying a material like Thompson’s Water-seal, which he did 2 years ago. The problem persists as the water-seal application has not worked. While this is a cosmetic issue and not structural, do you have a solution?

A.    Thompson’s Water Seal  was not the product to use for this purpose. It is paraffin-based and subject to fast degradation from the sun and other weather elements. The sealer to use should have a siloxane-base to allow the bricks to breathe. The mortar joints need to be sound and the chimney cap in good repair, or the brick treatment will not solve the problem. Unfortunately, the spalling can become a structural issue if allowed to progress too far, so it should be repaired.

Best stain to use on bricks

Q.    I have brick-facing on the front of my house. It is an orange/tan color. I would like to stain it dark brown. Is there a product for staining bricks?

A.    Yes, the bricks can be stained. You will have better success with a solid color, oil-based stain than with a semi-transparent stain. The end result will be as if you had painted the bricks, since solid color stains are really thin paints. Your local paint store will probably handle one or two brands and have some recommendations as to which one to choose.

Painting exterior brick

Q.    I would like to know your thoughts on painting exterior brick. I am in the process of evaluating different options of replacing the cedar siding on my 2-story split-level house. The house has a 3-foot or so high brick fascia topped with a limestone plate all around its perimeter.

This brick is a light shade of yellow, and will greatly affect (and limit) the choice of siding color. If you approve of brick painting, do you have any tips or gotchas to avoid ? Any ideas on how to keep the paint off of the mortar? Thanks!

A.    It is possible to paint certain types of bricks but the project is fraught with potential problems. If the bricks have a sandy-type feel to them, they cannot be successfully painted — the sand acts as a bond-breaker and the paint won’t stay on. If the bricks are smooth, they may be successfully painted, but if there is any moisture penetration either through the mortar joints, any joint with other materials, or from rising damp from the ground, the paint is likely to fail and you can end up with a mess. Paint adhesion also depends on how thoroughly clean the bricks are and the hardness of the brick surface. Yellow bricks may already have a coating on, making paint adhesion more successful.

Rather than paint, though, it is preferable to use a cementitious coating such as those made by Thoro. Check them out in a masonry supply house. The key to success is absolute cleanliness of the surfaces to be coated. The mortar joints must also be coated to eliminate any chance of water penetration.

Installing vinyl siding over brick

Q.    I am installing vinyl siding over brick with 1″x3” furring strips 16″ on center with 1″ thick insulation in between. Any suggestions you can offer would be appreciated. Should Tyvek go over the insulation?

A.    I assume the only reason you want to cover bricks with vinyl siding is because the house has no wall insulation. Otherwise, I wonder why you are doing it. Bricks are so maintenance-free whereas vinyl can be damaged if hit when cold, etc.

One inch by three inch furring strips are only 5/8ths or 3/4-inch thick, so you will need to use 3/4-inch rigid insulation between them.

Yes, use a housewrap over the insulation to protect the assembly from water that will get behind the siding. The rigid insulation will not be affected, but the furring strips may eventually degrade if they stay wet too long.

Repairing mortar between bricks

Q.    I have concrete steps in the front of my house and between some of the bricks the concrete has rotted out. I believe they call this pointing. My house is also brick and the same thing is happening in spots.

I would like to attempt to fix both of these things myself. Is it easy for an inexperienced  person and if not, what exactly do I need to do the job and what is the specific process?

A.    If I understand you correctly, you have bricks steps and the mortar between the bricks is deteriorating. The same is happening between the bricks of your house. (Concrete is a mix of Portland cement, sand and crushed aggregate and is used for concrete foundations, slabs, driveways, roads, buildings, etc.)

Tuck-pointing is what needs to be done, but since you are inexperienced, it is best for you to have a mason or handy person familiar with tuck-pointing do the job, particularly if the mortar crumbling is extensive.

Tuck-pointing requires the removal of all loose mortar, but with care so as not to cause serious damage. Once the loose mortar is removed, the joints need to be washed clean with a garden hose. Next is mixing the right mortar consistent with the age of the bricks (old mortar is different from newer mortar) and getting the right color so the repairs won’t stand out like a sore thumb.

As you can see, an amateur job may really detract from the overall look of the house. However, if you decide to make the repairs yourself, get a bag of ready-mix mortar from hardware or building supply stores, mix it following directions on the bag. Apply it to the cleaned joints with a small trowel and strike the joints with a joint tool or a short piece of garden hose.

Removing cement dust from bricks

Q.    I’m building a brick wall at my house, and when I clean with a wet rag the cement off the bricks it leaves me a white dust that doesn’t seem to come off. If there is a chemical that I can buy or what can I use so the brick looks clean without the white dust?

A.    Using a wet rag simply spreads the cement onto the bricks. You should only brush the bricks with a dry brush as soon as the mortar has dried to remove small mortar particles. Wait about a week before removing larger mortar particles with a wood or plastic scraper. Then, to remove smears, wash the bricks off with a 10 percent solution of muriatic acid (one part acid to nine parts clean water).

Mix the solution in a nonmetallic container by adding the acid to the water — never add water to the acid. Before applying the solution, saturate the bricks with clean water. Brush the solution and leave it on for 5 to 10 minutes. Rinse thoroughly with clean water.

Muriatic acid is very caustic; wear heavy rubber gloves, skin and eye protection and pour it slowly into the water container.