Restoration is a core element in our services here at CMR.
An innovative team of experienced masons dedicated to providing quality repairs and preventative treatments to various types of masonry systems and structures.
A combination of traditional and current techniques are used to provide essential and nonessential repairs and renovations to both common and unique masonry structures.
Proper removal and replacement of mortar joints are essential when repointing any structure. When done correctly, repointing will;
Increase structural integrity.
Ensure weatherproofing of structure.
Restore the overall appearance of the structure.
Raises property value.
Maintains the original character of the structure.
"Stronger mortar is the better mortar!" Not only is this not true but when the mortar is stronger than the masonry unit material, it can increase damage to the masonry units and reduce the structure's long-term durability. Mortar must have some flexibility or softness to accommodate movement while still maintaining a bond with the existing masonry materials. The mortar used for building a wall and for repointing should always be softer than the masonry unit.
Proper preparation of mortar joints should include the removal of old mortar to a minimum depth of two to three times the width of the joint to ensure an adequate bond and performance of the new mortar. Deteriorated mortar found past the minimum depth should also be removed.
For most structures, Type N mortar provides durability as well as enough flexibility to not damage the masonry. If the structure is constructed of sandstone or other soft stones, or soft masonry units, a softer mortar may be necessary.
Mortar shrinkage is one issue that requires much attention when repointing masonry. Mortar shrinkage can lead to cracked mortar joints. To minimize shrinkage of the mortar once it is in place, the mortar should be prehydrated. Prehydration consists of mixing dry ingredients together with only enough water that the mortar can be formed into a ball by hand. The mortar should then sit undisturbed for 30 minutes, then water is added until the mortar reaches a workable consistency, (hydration of cementitious material).
Mortar should be installed into the joints in three successive layers, install each new layer once the previous layer has set up so that it doesn’t deform under thumb pressure.
Repointing should be performed when ambient air temperatures are between 40° and 90° F.
In a high heat climate, it is important that enough water is maintained in the mortar so that proper curing and minimized shrinkage is ensured. This may require periodically moistening the wall during the curing process.
To prevent the mortar from freezing, repointing should NOT be performed when the outside temperatures are below 40° F for 48 hours or more during the curing process. If mortar freezes during the curing process, it becomes less durable and less weather resistant.
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Brick Replacement Guide
Start by identifying any damaged brick. Any bricks that are cracked in half, no longer full-sized, and/or soft enough to scrape out with a tool or figure should be removed.
To remove bricks, cut along the mortar joints closest to the brick that’s being removed using a 4” grinder or quickie saw. To keep the dust down, use a HEPA VAC compatible grinder or use the hose attachment on a quickie saw. These tools can be rented from a local tool rental shop or home improvement store.
Once the mortar joints have been cut, carefully dislodge the brick with a hammer. Watch the mortar joints near the remaining bricks in the immediate work area If there’s resistance, it’s possible those bricks could end up breaking due to vibrations and will need to be removed as well. Chisels can help make more precise strikes and reduce the chances of unwanted damage. Once the bricks and the mortar have been removed, wipe away any excess dust with a masonry brush. If the work area must remain clean at all times then you may want to consider using a HEPA VAC once again.
Time to relay some bricks! Start by mixing up the mortar in a bucket or if needed, rent a mortar mixer. Type N mortar is commonly recommended for brick units. Although, some historical buildings have softer masonry units. Which may require a softer mortar type. Mix the mortar with water until it’s roughly an oatmeal or pudding consistency.
Not all mortar comes premixed, so make sure you have a mortar sample properly analyzed by a reputable concrete/mortar manufacturer or supplier for the best results. They also can match your brick sample if need be.
Place some mortar on a trowel of your choice and lay it onto the brick wall. Add some mortar to one side of the replacement brick. Place it on top of the bed joint just laid in the previous step. Wiggle it into place and gently tap the brick using the backside of the trowel until it lines up with the other bricks in its course. Continue this process with the rest of the replacement bricks until the patch is filled. If the brick patch is large you may need to use a string line to ensure the brick stays straight and level each course.
Use a tuck-pointer to fill in all the joints as deep as possible. Depending on the jointing style, you may need to slick down all the new joints using an S-jointer. You could also use a stick jointer for a rougher looking joint. Maybe the existing joint pattern requires a roller-skate tool, etc.
After it dries a bit, wipe off any excess mortar on the face of the bricks using the masonry brush or other preferred hand tool. Careful not to smear your work. Once all the mortar has been removed, do a final pass with whichever striking method is relevant to the existing mortar joints.
Fedders Construction HQ
1102 Brighton St, Newport, KY 41071
There are many types of masonry units, lets take a moment to discuss two similar but unique types. When cleaning brick and terracotta, there are many things to consider. Although they are both fired clay, that doesn't mean they have the same properties or sensitivities.
An important factor to think about is the understanding of the material used, how they react with dirt on them, and how they might react when said dirt is removed.
Another factor is the mortar used in the construction of the masonry units. Traditional brickwork mortars consist of soft mixtures of lime and sand. Meaning that mortar is usually softer than the bricks themselves. When cleaning, If the mortar isn't considered it could unexpectedly suffer severe damage. The amount of weathering and its effects are also a vital part of understanding the material.
Any chemicals used on established brickwork should be low strength and neatly applied. Once left to sit for its necessary duration, it should thoroughly be rinsed at low pressures to ensure flow control and proper removal of chemicals. The porosity of the brick also needs to be taken into account. A more porous brick will have a higher absorbency which can affect, or even define, the parameters of chemical used.
Architectural terracotta became a trend in England during the 1800s and much of it remains standing today. It is one of the easiest materials to damage by incorrect cleaning. just like brickwork, the soiling likely found is not water-soluble. Both glazed and unglazed terracotta surfaces usually soil in heavily saturated areas, particularly areas closest to the mortar joints. Although the soiling on terracotta is generally an intense black, it is usually a thin and stubborn layer to remove. Techniques like abrasive cleaning, forms of mechanical cleaning, acid, and/or alkaline cleaning can cause severe damage if done incorrectly.
CMR offers several techniques to combat the soiling of masonry units. Have a conversation with a representative to discuss your unique situation.
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