[andyhome]

My house was built 100 years ago, is in the northeast and the pictures show the interior of the basement. The foundation is 18-24" thick made of stones set in mortar (no rebar or cinder blocks anywhere). I've been living in it for 20 years and the house hasn't settled any since I've moved in so the cracks you see are (I think) just old mortar pointing and dry plaster and paint peeling away. I haven't painted in 20 years so the paint is probably from 30 years ago. We have a very high water table AND the basement is around 4' below grade. It's pretty humid as a result but we don't have any seepage and I don't want to seal the wall with a dry-lock paint because I've read that that could cause different problems which we don't need to get into now.

So my pre-Christmas holiday project is to finally paint the stone and make it "nice" but the basement has a 6' ceiling so it's not useful as living or rec space. Just want the walls to be presentable. You can see some areas over the sink that I've painted in the past using excess paint leftover from other projects - basically I want to do more than that.

I know that I need to scrape off all loose paint and plaster, but then my questions are:
1) what to seal the long cracks with? a concrete caulk or just regular silicone or whatever's on sale?
2) do I need to prime it all?
3) I think I would want to use semigloss as the final coat because it'll be better as far as dirt goes plus it will brighten up the area.

Hopefully Home Depot has good enough quality paint for this. Behr? I usual buy benjamin moore paint but that seems too expensive and overkill for this project.

I appreciate any advice and direction you may offer!
Thank you,
Andy

 

[Nealtw]

Not silicone, you can not paint over it.
No suggestions on paint, if you have no leaks the high humidity is likely just the moist air from upstairs cooling in the basement. When air cools it can not hold the same amount of moisture.

 

[catheetiem]

A lot of that looks like lime mortar and parge coating. You should not paint it, it can damage the wall. Lime mortar and parge coating allows water through, paint will trap water behind it. You don't want this. These foundations were designed to have water pass through, they were never meant to be watertight living space. They are designed to allow moisture to pass through.

You can repair the cracks with lime mortar, not concrete or portland cement. Lime mortar allows water to pass through and will flex and move with any shifting, which is what you want. Chisel out whatever mortar is compromised and repair.

You can do a parge coat (that thicker layer looks like an older parge coat) with the lime mortar and finish off with a lime wash if you want to brighten the area up. Painting with regular paint or trying to waterproof it from the inside will only damage it. Modern materials are often a no-go for older houses, this is one of those cases.

 

[andyhome]

Catheetiem - Thank you. Can you send me a link to a version of LIME Morter that Home Depot would have? I've also attached two other photos to show some sections that I painted over the years. It's just normal semi-gloss Benjamin Moore paints which aren't made to seal the mortar so I think the wall can still breath and moisture can travel through. Btw, I called BEHR and they recommended the following paint, although I do not think they thought I have LIME morter: Interior / Exterior Masonry, Stucco, and Brick Satin Paint | Behr

 

[ClarenceBauer]

Catheetiem - Thank you. Can you send me a link to a version of LIME Morter that Home Depot would have? I've also attached two other photos to show some sections that I painted over the years. It's just normal semi-gloss Benjamin Moore paints which aren't made to seal the mortar so I think the wall can still breath and moisture can travel through. Btw, I called BEHR and they recommended the following paint, although I do not think they thought I have LIME morter: Interior / Exterior Masonry, Stucco, and Brick Satin Paint | Behr

Catheentein is correct on her statement.
Please NOTE Lime mortar Or Lime wash will not adherer to a painted surface.

 

[catheetiem]

Catheetiem - Thank you. Can you send me a link to a version of LIME Morter that Home Depot would have? I've also attached two other photos to show some sections that I painted over the years. It's just normal semi-gloss Benjamin Moore paints which aren't made to seal the mortar so I think the wall can still breath and moisture can travel through. Btw, I called BEHR and they recommended the following paint, although I do not think they thought I have LIME morter: Interior / Exterior Masonry, Stucco, and Brick Satin Paint | Behr

Unfortunately real lime mortar is not available at home Depot. We use limeworks lime mortar:

Ecologic™ Lime Mortar - Natural Hydraulic Lime Mortar

Ecologic™ Mortar, in any of the stock colors, is simply a prepared blend of lime binder/aggregate/pigments to which you just add water, mix and go to work.

www.limeworks.us

If you scroll down to the very bottom you can find a map with retailers. Unfortunately they're pretty spread out. I saw that you said you're in the northeast, we're in CT so we go to Hudson valley house parts in Newburgh, NY to get ours. There are a bunch of retailers in PA, the one in newburgh, and a few in upper new England. You can also order directly from them but you do have to pay for shipping.

If their retailers are too far you could try contacting a couple of masonry supply stores near you, they might be able to help though I can't say for sure. Be careful with them too, some might try to tell you Portland or a mixture will be fine. They're lying or uneducated. We had 5 masons out to our house and not one wanted to use the proper materials (this is why we ended up doing it ourselves). One even said the mortar doesn't exist anymore and we would have to rebuild our whole chimney! Absolute garbage.

Unfortunately any paint, oil or latex, will trap moisture behind it and damage the wall. A little here and there isn't the end of the world obviously, but I would definitely avoid painting the whole thing with any paint. You're correct in thinking that behr doesn't understand that you have a historic home that needs to allow moisture to pass through. That's a latex paint like any other. Think about how we use paint on exterior surfaces-to stop water intrusion into wood and prevent rot. The effect on stone and mortar is the same, it will prevent moisture from going through, only in this case moisture passage is the goal. I have some brick portions of my foundation that were painted over, it's now crumbling off and the brick and mortar is turning to dust behind it. I'll take some pictures when I go down there tomorrow morning.

We're planning on using limeworks limewash when we do ours:

Ecologic™ LimeWash Platinum - Whitewash - LimeWorks.us

Eco friendly, made in America & beautiful, Ecologic™ Limewash Platinum (whitewash) is a perfect compliment to lime plaster & suitable for most applications

www.limeworks.us

It's made from lime so it is breathable. Other companies make limewash too, but we've been happy with limeworks so we'll continue going with them.

Limeworks also has a ton of educational material and videos. I'd highly recommend checking them out. They're one of only 2 places in the entire country that produce it. They actually do the work too, they're based in VA and they actually sent a crew up to repoint the smokestack in my old apartment, converted from a late 19th c factory (I didn't realize it was them at the time, only later did I put two and two together haha). Little did I know a few years later I'd be buying their mortar for my own house!

 

[andyhome]

Boy, when i posted my question I never thought I'd be getting into something so involved and 'off the beaten path'. So my understanding is that 1) clean and scrape off all loose paint or parge coating, 2) use LIME MORTAR to fill in the cracks, gaps and whatever other surface I want to look better, 3) use LIME WASH to wash and update the color.

So the LIME WASH is like a paint ?

A lot of the wall and stones have 50 years of dust/dirt on them so I guess I will need to really scrub those clean. I'm guessing I should be using some kind of LIME CLEANER ?

Previously I thought I'd clean it loosely and then use a primer and then paint.

Thanks !

 

[catheetiem]

Boy, when i posted my question I never thought I'd be getting into something so involved and 'off the beaten path'. So my understanding is that 1) clean and scrape off all loose paint or parge coating, 2) use LIME MORTAR to fill in the cracks, gaps and whatever other surface I want to look better, 3) use LIME WASH to wash and update the color.

So the LIME WASH is like a paint ?

A lot of the wall and stones have 50 years of dust/dirt on them so I guess I will need to really scrub those clean. I'm guessing I should be using some kind of LIME CLEANER ?

Previously I thought I'd clean it loosely and then use a primer and then paint.

Thanks !

Haha yeah things can get tricky with old houses!!

Here's what's happened with the brick that was painted on my foundation. Please excuse the mess and the great stuff, I haven't gotten to this section yet. Underneath that white is lead paint so some form of paint has been on here for at least 50 years.

Here is where the brick meets the stone, the water being trapped has disintegrated the mortar and it's turned to dust:

Here the pressure has broken down the paint and you can see the disintegrated mortar. The white crystalized looking stuff is efflorescence from the water being forced through the masonry, leaving behind salt and mineral deposits. Not harmful or dangerous to your health but an indication of water/moisture:

Zoomed out. That texture is the paint pulling away from the wall because of the mortar dust building up behind it:

More mortar dust breaking through, you can see a big chunk is completely gone:

This brick here has actually spalled and is disintegrating. There may be more like this that I just haven't uncovered.

And here again to show texture, all those bumps are from the mortar disintegrating and pushing against the paint because the water can't evaporate out. You can see some here and there have started to crack.

Yep, you're right on the procedure! You can parge coat in between the repointing and limewash if you would like a smoother/cleaner texture. Parge coat is basically watered down lime mortar so it will be able to breathe. And yep, lime wash acts as paint in this application.

You don't need to go too crazy with cleaning and there's no specific cleaner to use. We just brush off with a masonry brush and then spray with water (spraying with water is necessary for adhesion too). Vacuuming it can work well too. If there's any portions that are caked with dirt or anything you can go at it with a warm water rag or something but there's no specific cleaner for it. A little residual dust/dirt is ok and you'll never get it totally clean, but it shouldn't be totally covered or packed with it cause the mortar will stick to that rather than the stones.

 

[andyhome]

Hi. Didn't want you to think I've ignored this thread. Thanks very much for the pictures, I just haven't been able to do my local research except to go to the local stone and pavement center (they are huge! Sammarco Stone & Supply, Inc. | Stone, Masonry, Drainage, Outdoor Living Supply in New Rochelle, NY)

Our basement walls seem to be different. I have ZERO bricks. What I have are basically huge boulders (18-24" in diameter) with lime mortar filler. I definitely have the same mortar disintegration you have but my boulders are fine and I have no bricks that can fall apart.

The fellow at sammarco, said:
1) yes they have mortar with lime which I could use for parging (he said 80 lb bag of quikrete)
2) suggested Thoroseal as a cement-based coating.
He was perplexed at my concerns because "everybody I know wants to keep moisture/humidity OUT of their basements" and said the thing to do would be to rubberize the wall from the exterior (which I can't afford to do - would cost me $50,000 as I live in a easy-pickings rip-off-the-wealthy town (which I'm not)

 

[catheetiem]

Hi. Didn't want you to think I've ignored this thread. Thanks very much for the pictures, I just haven't been able to do my local research except to go to the local stone and pavement center (they are huge! Sammarco Stone & Supply, Inc. | Stone, Masonry, Drainage, Outdoor Living Supply in New Rochelle, NY)

Our basement walls seem to be different. I have ZERO bricks. What I have are basically huge boulders (18-24" in diameter) with lime mortar filler. I definitely have the same mortar disintegration you have but my boulders are fine and I have no bricks that can fall apart.

The fellow at sammarco, said:
1) yes they have mortar with lime which I could use for parging (he said 80 lb bag of quikrete)
2) suggested Thoroseal as a cement-based coating.
He was perplexed at my concerns because "everybody I know wants to keep moisture/humidity OUT of their basements" and said the thing to do would be to rubberize the wall from the exterior (which I can't afford to do - would cost me $50,000 as I live in a easy-pickings rip-off-the-wealthy town (which I'm not)

No worries!! Yeah, my basement is half brick and half stone. I was trying to show how paint keeps moisture in by showing the deterioration of our mortar and brick. Our stone has never been painted so nothing of note there.

Here's what it looks like, full view. Generally (but not in all cases) the brick is above grade and the stone below grade. Here you can see the previously mortarted sections, near the top and where it looks like a window might have been filled in. Down lower I'm still uncertain if it was ever mortared or just dry stacked. Either way, we've pointed it now (this picture is before):

Here you can see some parge coating on the bricks. Notice everything's in fine condition. I just repointed this section last weekend (after the picture was taken) and it only needed a couple sections here and there, very minor. This is the difference between using parge coating and using paint.

Ah if you're in new rochelle we're quite close-I'm in fairfield county in CT! Yes, many people would prefer to keep water out of their basements. For a concrete foundation that's exactly what you try to do. People with stone foundations also probably try to do the same-though mistakenly.

That quikrete he suggested isn't lime mortar. It's mortar that CONTAINS lime, as all mortar does, but it also has cement. True"lime mortar" is pure lime mortar-it is only made up of lime and sand. The quikrete is entirely inappropriate for a fieldstone foundation.

Look, I don't want to say this guy's wrong, but like....he's wrong lol. Cement will absolutely destroy your foundation and is the arch nemesis of historic masonry. Please do not put concrete or cement on your foundation. There is a lot of excellent information here, I would really recommend reading it:

General Installation Guidelines - LimeWorks.us

www.limeworks.us

It [mortar] should not however set and harden so quickly that it becomes inflexible at any stage and cannot accommodate slight movement. There is normally no requirement for significant structural strength in the mortar of traditional masonry buildings, particularly in re-pointing work. Mortar should be permeable in itself, both so that the quantity of free water on the face of the building is reduced, thus reducing the possibility of wind-driven water penetration and so that moisture evaporation is not concentrated in the masonry, which may then be vulnerable to accelerated breakdown in the vicinity of the joints.

Most important of all: the new mortar should be compatible with the old. Do not introduce mortars containing potentially damaging elements or that can constitute an impermeable barrier obstructing vapor exchange and retaining moisture. The consequences in a relatively short time could be disastrous and, in most cases, irreversible.

Here's a blog post about it with a couple FAQs:

Repointing a Stone Foundation with Lime Mortar - Blake Hill House

Stone foundations need regular inspection and maintenance. Repointing a stone foundation with lime mortar is a simple DIY task. (Video + Q&A)

www.blakehillhouse.com

If you'd like you can give the guys at limeworks a call. They are very helpful and will absolutely give you advice and guidance on what to do. Yes, you want to keep the basement as dry as you can, but you do not want to make it watertight. The basement is going to have water intrusion no matter what because of the way it is constructed, there is nothing to do about that short of excavating and pouring concrete all around the outside (waterproofing coatings can be iffy). Drainage and grading will help, but there will always be moisture getting in, that's simply the nature of stone foundations. That moisture then needs to be released, so waterproofing from the inside is a recipe for disaster. Unfortunately the guy at the masonry place did what I thought they might-give inappropriate advice based on a lack of understanding of the characteristics and needs of historic masonry.