How long it takes for brick mortar to dry. A lot of masonry beginners confuse mortar and concrete. They can look the same, and some people figure they’re just different names used for different build uses.
This, however, is not true. Mortar and concrete are commonly used in building projects, but incorrect application of one when building calls for the other can cause structural issues in your build.
Mortar is used to bind materials like stone and brick together. The water content is higher in mortar than it is in concrete to enhance its ability to bond.
It’s made from cement, sand and water, and is generally much thicker than cement when its mixed together. Modern mortar is much more durable than older mortars.
Knowing how to properly apply mortar will make a huge difference in any masonry project you undertake. The improper application of mortar can create structural weakness in whatever is being worked on.
Failure to let mortar dry can also cause issues. Adding additional weight onto wet mortar can shift tiles, bricks or stone that have already been placed. So, how long does Mortar actually take to dry?
Here are a few things you can do to make sure you’ve got it right.
A Note on Cure Times
Mortar needs to be kept wet for around 36 hours so it can cure fully. There’s always some risk with brick mortar when dealing with weather and other external factors.
If it’s dry and hot, it could pull the moisture out of the mortar and cause it to shrink, sucking it away from the bricks. If things are too wet and cold, too much water can seep into the mortar weakening its ability to bond materials together. If you’re in for turbulent weather, cover the mortar work with tarps or shelter so it can cure well.
Some DIY masons, and professionals even, have been bitten by the promise of short cure times on pre-mixed mortars when they’re doing smaller projects.
The instructions say that the mortar will take “x” hours to cure in place, but after the allotted time, materials still shift. Thin-set mortars that come in a bag sometimes require much longer time to cure than even the labels on them say.
They’re usually reliable, but their dry time will depend on nailing the mix consistency. Experts say to target the consistency of pancake mix or mayonnaise when you’re mixing thin-set mortar.
Problems can also arise when people use improper trowel notch sizes. Notches affect how much mortar is applied which could either shorten or extend dry times.
A general rule of thumb is to let it set for 24 to 48 hours. If you’re in a humid climate, time requirements are likely to be greater.
Not every job is going to be able to be completed with thin-set mortar. Heavy duty mortars used in brick walls, fireplaces and other large-scale projects take more time.
Brick mortar is commonly made with Portland cement, which will dry fairly well in the first 24 hours. The mortar, however, will still contain a lot of moisture, and will not reach full strength for days or even weeks. Builders won’t get an idea of the actual final color and look until it’s been set for two weeks.
What to Do in Case of a Mistake
Unfortunately, due to the materials used, and the need for mortar to be strong and long-lasting, the stakes are high when it’s applied to brick. There’s no mortar eraser after it’s cured and set.
Common mistakes when applying mortar
The most common error in mortar work beside how long does mortar take to dry is using modern mortar on brickwork that’s decades, or even centuries old.
- Older generations of mason workers used lime-based mortar that was softer than modern day mortar. Mixing the use of the two in the same wall or structure can cause significant damage.
- Another common mistake people make is being unaware that the color of mortar changes from when it’s wet to when it’s dry. Consult whoever you’re buying mortar mix from on what to expect in terms of final color. The worst thing that can happen is to apply mortar onto bricks and be unhappy with how it looks. Really there are few options to change the color. To totally fix it, the wall, fireplace, patio, or whatever is being built will have to come down.
The project will need to be started from scratch again. Other solutions can try and mask the other mortar, but it won’t look perfect. The correct shade of mortar can be applied along mortar lines like a topcoat. However, the mortar lines will likely look thicker than normal. As a fix, think about digging out a layer of mortar and filling in from there. Some people try and paint the mortar lines, but this doesn’t give off the distinct look of natural cured mortar.
Steps to Get Mortar Drying Right
Follow these steps to get things right the first time.
1. Wet the bricks – Soak the bricks in water before you put mortar on. This will slow the time it takes for mortar to dry so the mortar can seep fully into the bricks’ pores and create a stronger bond. Soak the bricks overnight the day before the mortar’s being applied. Do what you can to keep them moist as the building process takes place. It will make a big difference.
2. Intermittently Spray the Mortar – Use a hose or spray bottle, depending on the size of your project to spray the mortar down every hour or so. It will help with step 1. Keep doing it for a few days after everything’s finished. Make sure the water pressure isn’t strong enough to move the mortar.
3. Keep Things Covered – When no work is being done on the project, keep it covered to hold moisture in. Again, this will help the mortar create a stronger bond between bricks and stone to make it as durable as possible. If mortar is not kept wet for the proper amount of time, the bonds will be weak, and it will affect the lifespan of the structure.