Masonry Repair on American Fork Chimneys

That deserves explaining before anything else, because it is the difference between a repair that lasts and one that destroys the wall it was meant to save.

Hard mortar against soft brick

Brick made locally a century ago is comparatively soft and porous. The lime-based mortar it was laid in was softer still, and deliberately so. Masonry moves, and in an old wall the mortar is the sacrificial part: it takes the stress, it cracks in preference to the brick, and it can be replaced.

Modern Portland cement mortar is much harder and much less permeable. Point an old chimney with it and you reverse the relationship. Now the mortar is stronger than the brick, so the movement and the trapped moisture have to go somewhere else, and where they go is into the face of the brick itself. It spalls. The face flakes off, exposing the softer body underneath, and the next winter takes more. You see the result on plenty of older stacks around town: crisp grey joints standing slightly proud, with the brick between them eaten back.

So on pre-war work we match the mortar to what is there, in strength as well as in color and joint profile. It is slower, it is less profitable per hour, and it is the only version of the job that is actually a repair.

What we repair here, in order of frequency

Crowns first. American Fork sits on the valley floor and takes wet Wasatch storms, and a thin, cracked crown lets that water straight into the top of the stack. Then flashing, where the chimney passes through the roof, which is the source of most leaks that owners assume are chimney leaks. Then joint erosion, then spalled brick, then smoke chambers and fireboxes.

Rebuild, and when it is honestly the answer

Above the roofline is where stacks die. The masonry up there is wet on every side, has no house heat behind it, and takes the full freeze-thaw cycle. When the top courses have gone soft, taking them down to sound material and rebuilding is the durable answer, and patching is money spent on delay. Below the roofline, full rebuilds are rare and we will usually be arguing you out of one.

Newer construction, different repairs

On the subdivision side of American Fork the chimney is often a framed chase with a veneer, and the repairs there are flashing, chase covers and siding rather than masonry. Same water, different failure, and we would rather tell you it is a carpentry job than sell you tuckpointing.