Repairing/replacing grout in brick ?

Old 04-02-19, 12:24 PM
Thread Starter
Join Date: Oct 2009
Location: Dallas, TX
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
Repairing/replacing grout in brick ?

My house has some deteriorated mortar between bricks on an upstairs window sill and the brick header across my downstairs livingroom upper window. One is above the other. The house was built in the 90's and this is the only place that has washed out grout.

I dont know how it got in the shape its in but it needs attention. The grout that should be there has been replaced by a heavy duty caulk of some kind. Its doing the job but it wont last forever so I thought I might take a shot at fixing it myself.

A cutoff saw with a braided wire wheel to clean out the between brick spaces and then re-grout?

Im open to suggestions.
Old 04-02-19, 04:21 PM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 27,517
Received 2,114 Upvotes on 1,893 Posts
First, grout is used cosmetically between tile. Mortar is a different product used to bind brick. The process you described is "re-pointing". But your plan sounds good. Since caulk has been used you need to thoroughly clean the brick so mortar can adhere. Since it's above grade type N mortar will be fine but you can also use type S if you already have some on hand.

If you have never done masonry work wear gloves. Many people find it difficult to keep their hands out of mortar or they resort to using their hands to work the mortar. While mortar doesn't really hurt you it will thoroughly dry out your hands even with short contact.

When pointing your joints work very hard to make sure no mortar touches the face or pretty part of the bricks. Even if you think you got it all off the mortar will leave a white residue when it hardens and dries. So, working clean and neat up front will save you a lot of work cleaning mortar off the face of the bricks.
Old 04-02-19, 04:31 PM
Join Date: Jan 2014
Location: USA near Boston, MA
Posts: 2,246
Received 387 Upvotes on 337 Posts
Ask This Old House recently showed how to do that:
Old 04-10-19, 06:18 PM
Join Date: Sep 2008
Location: Richmond,Va
Posts: 50
Upvotes: 0
Received 0 Upvotes on 0 Posts
Try to get the same color mortar that was used previously. You may have to go to a brick supplier to get what you need, big box stores only carry a small sample of whats available.
Old 04-11-19, 03:52 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 45,617
Received 824 Upvotes on 722 Posts
White versus brown sand also affects the mortar color. Personally if that's all the mortar that needs to be replaced I'd just get it a bag of premixed mortar [just add water] to replace the missing mortar. The odds are the color won't be the same but unless you were to intermix or tint mortar to match the old aged mortar it will show anyway. I have on a few occasions mixed up some thin paint to 'color' the replaced mortar so the color difference wouldn't stand out.
Old 04-11-19, 04:35 AM
Join Date: Nov 2012
Location: USA
Posts: 2,291
Received 283 Upvotes on 243 Posts
Originally Posted by 4135V
Try to get the same color mortar that was used previously. You may have to go to a brick supplier to get what you need, big box stores only carry a small sample of whats available.
Before I re-pointed our old farmhouse, I mixed up multiple batches of mortar to create a grid of 32 colors, representing 4 different colors of sand, and 8 different mixes of lime and white/black/red tinted cement.

So, I'd start by scraping off a small piece (chicklet or asprin sized) of the old mortar into a small cup, add white vinegar to dissolve the mortar and check what color sand the mortar used. Then match the color of the sand.

Once you know the color of the sand, grab a few different 1 lb bags of colored cement. Mix a few samples, let them dry, and see what matches.

Oh, another quick tip- set out a tarp to catch the chips, tehn chisel out the surface mortar for 1 or 2 brick courses BELOW the section that you have to repoint.
Grind up the old mortar, (e.g. a metal bucket and 5lbs sledge hammer used like a milk churn) then add some ground up old mortar as aggregate in the new mortar. Use more "old ground" for the course adjacent to the "old mortar" and less as you move up. That "blends" the color from the old to the new over a few courses of brick,

Thread Tools
Search this Thread
Ask a Question
Question Title: