Repointing an 1800's Stone Basement

[redstrosekNic]

Hi All,

Wondering if there are any experienced masons who could weigh in on this - I'm repointing a few walls in my basement. I'm using the correct mortar (containing no Portland cement). Parts of the area I'm doing have dirt higher on the walls than other areas. Do I dig away at the walls so they are all exposed the same amount, or do I just repoint what I can see? Any guidance would be appreciated.

Thanks!

[Crowbob]

Very carefully examine the old mortar. Way back when it wasn't the best stuff. It's not uncommon for it to have 'calcified' (my word) into a grainy crumbly dust.

[redstrosekNic]

Originally Posted by Crowbob

Very carefully examine the old mortar. Way back when it wasn't the best stuff. It's not uncommon for it to have 'calcified' (my word) into a grainy crumbly dust.

There are lots of areas where the mortar is washed out from the previous homeowner allowing the gutters to overflow on a particular corner of the house.

I'm wondering if I should dig away at the dirt higher on the walls in certain areas, or just leave it be.

[stomachmonkey]

Me, I'd seal that obvious demon portal from hell shut, put the house up for sale and live somewhere else while that was happening.

[bpu699]

You want commercial mortar WITH cement.

If you are tuckpointing soft brick from that era, you want soft mortar. Mortar must be softer than what you tuckpoint.

For stone, which is ROCK hard, you are ok with commercial grade mortar.

Not a mason, but own tons of buildings from that era.

Loosen up any old mortar, one section at a time, then powerwash between the stones. Then, get a squeeze bag, and shoot it between the stones as deep as you can...

Good luck.

Bo

[MRM]

Yes, very carefully scrape the dirt level. I’d try to remove it down to the original level.

[Captain Ahab Jr]

My house is lat 1700's and stone and I've repointed most of it inside and out

To remove the old mortar use a small pick and scrape out about an inch deep, brush out any loose stuff with a stiff brush (similar bristles to a hard yard broom) and then use a finer brush (similar bristles to a good house broom)

DON'T use a power washer as you'll just make a big wet mess and then have to wait days for it to dry out

A mix of 1 part lime, 1 part cement and 6 parts sand should be a good mortar mix. Just fill the joints to flush over flush with a small trowel, allow it to dry partially until its crumbly to touch.

To clean off the excess mortar, scrap any excess flush with the stone using your trowel and then wire brush diagonally across the joint. Do the same again use a softer brush to get rid of the wire brushing marks.

[Captain Ahab Jr]

Here is a wall we built from scratch a couple of years ago

Actually this is our view and my wife did this side


I did this side and this is neighbors view

[Steve F]

^^^^ Nice!!

[bpu699]

Originally Posted by Captain Ahab Jr

My house is lat 1700's and stone and I've repointed most of it inside and out

To remove the old mortar use a small pick and scrape out about an inch deep, brush out any loose stuff with a stiff brush (similar bristles to a hard yard broom) and then use a finer brush (similar bristles to a good house broom)

DON'T use a power washer as you'll just make a big wet mess and then have to wait days for it to dry out

A mix of 1 part lime, 1 part cement and 6 parts sand should be a good mortar mix. Just fill the joints to flush over flush with a small trowel, allow it to dry partially until its crumbly to touch.

To clean off the excess mortar, scrap any excess flush with the stone using your trowel and then wire brush diagonally across the joint. Do the same again use a softer brush to get rid of the wire brushing marks.

power washing accomplishes 3 things...

1) Cleans the old mortar dust off the stone. If the stone isn't clean, the new mortar doesn't stick
2) Wets the stone, which helps form a stronger bond. You can mist the stone also, accomplished the same thing. If the stone isn't moist you may get a dry set, where the mortar dries, but doesn't stick...
3) Gets the weak mortar out better.

You could do the same with a hose...

Yep, its messy

[Captain Ahab Jr]

Originally Posted by bpu699

power washing accomplishes 3 things...

1) Cleans the old mortar dust off the stone. If the stone isn't clean, the new mortar doesn't stick
2) Wets the stone, which helps form a stronger bond. You can mist the stone also, accomplished the same thing. If the stone isn't moist you may get a dry set, where the mortar dries, but doesn't stick...
3) Gets the weak mortar out better.

You could do the same with a hose...

Yep, its messy

I get it but I'd never attack an old stone house with a power washer rather than the gentler approach with a brush

With a house that is that old you may find below an outer mortar layer the stone is held together with mud and horse hair and the internal wall cavity is just loose rubble

[DanielDudley]

A grout bag is your friend.

[DanielDudley]

Originally Posted by Captain Ahab Jr

I get it but I'd never attack an old stone house with a power washer rather than the gentler approach with a brush

With a house that is that old you may find below an outer mortar layer the stone is held together with mud and horse hair and the internal wall cavity is just loose rubble

It's a fine looking foundation wall, the kind it is hard to get apart because the stones all fit together. I too am pretty happy with a long handled brush and a five gallon bucket for washing down the wall.

A respirator is a must for getting the old mortar out, and the dirt out. If you can figure out a way to use a fan to pull air out of the space, it would be a great boon to your project.

[flatbutt]

Originally Posted by Captain Ahab Jr

A mix of 1 part lime, 1 part cement and 6 parts sand should be a good mortar mix.

A question on uniformity if I may. I've done a similar mix but 4 parts sand and only small batches. For those I would smear out a handful with my trowel and if I saw any sand colored streaks I knew I had to mix longer. Do you do something similar?

[redstrosekNic]

Thanks for the replies! I will scrape away the dirt to expose as much of the wall as I can. I love these kinds of projects!

[daepp]

Ahab - that is one fine wall. How long did you and your bride work at that?

[red-beard]

You want the dirt level BELOW the wooden sills, or the sills rot. I owned an 1824 farm house with stone foundations in far Western Massachusetts.

[Captain Ahab Jr]

Originally Posted by flatbutt

A question on uniformity if I may. I've done a similar mix but 4 parts sand and only small batches. For those I would smear out a handful with my trowel and if I saw any sand colored streaks I knew I had to mix longer. Do you do something similar?

I used to mix it in a bucket but then bought a electric cement mixer which really made it easier.

I normally add half the the sand and make a runny mix which is easy to mix. Then add the rest of the sand in small amounts with extra water as required. Find it mixes better as if its too dry its easy to get sandy streaks.

Originally Posted by daepp

Ahab - that is one fine wall. How long did you and your bride work at that?

Thanks, it was our first wall and very pleased with it.

We also took down the old dry stone wall (no mortar used back then) which was half the height and dig the foundations.

All in all about 11 weeks, 7 day weeks and long days, I really enjoyed working outside
and hard manual labour is good for the soul too

[daepp]

Very impressive!

[GH85Carrera]

Originally Posted by Captain Ahab Jr

Here is a wall we built from scratch a couple of years ago

Actually this is our view and my wife did this side


I did this side and this is neighbors view

Impressive. I bet that took a couple of long weekends.

My wife and I built a SMALL decorative flower garden dry stack wall and that wore us out. It does hold back some soil, but no real load.