Basements, Attics and Crawl Spaces - Does mortar need to cure?

Does new mortar need to cure, if so for how long before it can be sealed?
I'm working on sealing my basement. Some of the old mortar wasn't very good so I chiseled it out and replaced it with new mortar mix. (I tried hydraulic cement, but it set too fast for the amount of area I had to deal with.) I want to eventually seal it with Drylok.

Do I have to seal the newly mortared areas with something first or can I just paint on the Drylok?? Also should the new mortar be washed with vinegar? Someone recommended to me that I wash the walls down with vinegar to make sure they were good and clean and no dust had settled into the nooks and crannies of the block.

Usually about 30 days for cement type products, but drylock is also a cement type product. So not sure what to recommend.

There are some schools of thought that say not to seal from the inside. Their thinking is, if you don't allow a direction for the moisture to go, then it will build up until it finds a way in.

Eliminating or at least reducing moisture problems in a basement start on the outside with landscaping and drainage to move the bulk of the water away from the foundation. Next is sealing on the outside of the foundation walls, I know, hard to do on an existing home. If water is still able to enter the basement, then a perimeter drain system to control and remove the leakage. If it is just moisture, then a de-humidifier should be able to handle it. Here are a couple of links to help.
RR-0509c: Renovating Existing Basements — (http://www.buildingscience.com/documents/reports/rr-0509c-renovating-existing-basements/view?searchterm=basement)
BSD-103: Understanding Basements — (http://www.buildingscience.com/documents/digests/bsd-103-understanding-basements/?full_view=1)

Bud

Hydraulic cement has been used successfully for decades on commercial, industrial and civil projects (dams, etc) if it used correctly and forced into a crack/joint. It must be prepared in small batches because of the rapid rate of setting and the future expansion to lock it into a void. Drylok is not an adequate material to use as a replacement for improving mortar or joints. I think "Drylok" repackages hydraulic cement and sells it at a higher price than the generic material that has been used for years.

There may be better alternative products to "Drylok" for applying to a wall. In all cases, the preparation is important. Applying an acid (like vinegar) can kill the further curing of the mortar or any other cement-based material.

Mortar is an entirely different "animal". Like all cement based materials it will continue to increase in compressive strength (if that is what is wanted and really is not that important). Some even suggest spraying the wall with water before application.

Mortar will gain a lot of strength in the first 7 days or so (maybe 60% to 80% of the ultimate strength). Strength is not the main concern for mortar, since bond and long term strength gain are more important.

The fabled 28 days of curing is just that (a "FABLE") when it comes to curing concrete (that 28 day period is the time required in the laboratory to achieve the design strength that is often not important and often 2 or 7 days tests are used before loads are applied on major structures.

Dick

Basically what I'm doing it cutting out sections where the mortar has failed and replacing it. Strength isn't really an issue unless at some later point in time the new mortar won't support weight around it if the mortar next to it fails.

I realize fixing the problem from the exterior is the correct way to proceed. However most of my house would be inaccessible to excavate using a backhoe. It would therefore have to be done by hand which would increase the cost 10 fold. Not an attractive idea.

The area around the house has the appropriate slope to it, took care of that this summer. Also had a new sewer pipe out to the public sewer line put in. The problem is the exterior of the house was sealed with tar, as was the practice back in the 50's. They did a half ass job on what they did cover and what they missed has been leaking water into the blocks ever since. I also believe that a block wall should have the first 3 or 4 courses of blocks filled with concrete. That wasn't done either. (I've also discovered this house has little to no insulation between the studs, another project for another time).

I have been looking at this product called Xypex. It sounds like the ideal solution. From the sounds of things it doesn't just seal the block like Thoroseal or Drylok, but fills the pours deeper. If I understand it correctly, it eventually grows and fills the whole one side of the block and mortar, thereby not letting any water to push through the block to cause seepage???

I just can't find anyplace in the Rochester area that might carry it. I'd like to do the floor too so I don't want to have to ship a large quantity of the stuff clear across the country.
Anybody know of someplace in NY that sells it????

To find Xypex, the best suggestion is to use Google to find the manufacturer, then the distributor and then dealer. Hopefully you will find someone close to you.

I had a friend that sold Xypex about 30 years ago, so it is not new, but it never really went anywhere.

Don't feel bad about the lack of grout in the cores of the first courses, since it really has little effect. I knew a large builder (3000 - 5000 homes) that never would allow grout in the cores and even had a special block made to provide better water control. He never had a leak or complaint. - He use only Thoroseal on the exterior of the wall and applied (not sprayed) a black coating to hold the 6 mil poly to the exterior.

Dick

Dick
I have Thoroseal on it right now, but it's been on there about 10 years. The problem is in some spots it has effloresced behind it causing it to bubble up off the wall allowing water to seep through again.
I've been trying to strip the whole wall to start over. I've heard grinder mentioned a few times, is that the only way to get it off where it doesn't want to come off?? I tried a chemical stripper, even with good ventilation the fumes stunk up the whole house.

I found a dealer for Xypex in Buffalo, about an hours drive from me. Is Thoroseal the same sort of product, or is Xypex an whole different animal in a category by itself???

Xypex is a totally different type od material. It supposedly penetrates (if you use enough) and creates crystals that impede the moisture.

Thoroseal is an old time cement based product that bond very well into and to the concrete, so it can be very hard to remove unless you use mechanical means. Any solvent that removes the solvent will also damage the concrete. Thoroseal's advantage is the durability and it can (and should be) applied to a damp wall. The additives (latex) make the material bond better initially.

If you have signs of efflorescence, you have water behind the wall finding a way to show up somewhere (even on a different wall) on the inside.

I still (after 40 years experience) don't understand why so many builders are so stupid and cheap to not put in drain tile, considering the low cost when building. If you get rid of the water, there is little need for "tar", plastic and organic materials that will eventually deteriorate.

Been doing some reading on the prep and application for this Xypex. Not sure if I want to tackle this after reading that. It says you need to sandblast the old stuff off the walls, then wipe the walls with Muriatic acid to get all the nooks and crannies clean, then flush with water. Then you have to spray the walls 3 times a day for 2 to 3 days with water to keep it moist so it cures properly.

Did I mention my wood shop is in this area?? Wood and water don't exactly work to well together. Not to mention a few thousand dollars worth of machines and hand tools getting rusted from excess moisture.

I still have a full bucket (unopened) and a partial (dry) of the Thoroseal I used before, is that still good to use, or do I need fresh stuff?

Also, if I do use Thoroseal, do I have to remove the old, hard to remove stuff since I'd be using the same product??

You said I could have efflorescence from one wall affecting another. How, I don't understand???

Xypex can take a lot of cleaning if you want to get enough on and penetrate the wall surface. A sound coat of something could stop it from getting into the concrete and forming crystals.

You can make the Thoroseal work better and be easier to apply if the wall is is moist, but not running wet. They recommend misting before application, but no long tern mist, but a little the next day would not hurt. A latex product (Acryil 60 is one, but there are many different similar products) increases the bond to the existing cement based materials. Since Thoroseal has been used for many years, there are probably unbranded knock-offs.

Your old Thoroseal may be OK depending on the age and conditions it was stored in. A bag or pails of the powder is not that expensive. Make sure you mix it according to the instructions and let it sit to "fatten" up and then add water if necessary and remix before applying.

Thoroseal is sloppy to work with, but keeping the wall moist prior to application makes the application much easier.

My 12 year-old son and his buddies had a Thoroseal fight one time and it washed off them easily since it was done before drying.

What about the Thoroseal that is still on the wall and is sound can I go over it? Is it better to not go over it?

What I bought was in metal pails. The pail that is open is still powder. The other pail was never opened. I bought way too much of the stuff.

I remember it being a bit of a job to put on. I had it in my boots, all over me, hair, glasses and everywhere. They were old cloths so I just threw them out when I got done. I can imagine a paint war with that stuff:D I remember going through 2 brushes too before I got the job done. It wore the bristles down to a nub.

I copied down what you said about mixing, what is "fatten"?
How do I know if it's the right consistency? If I remember it was like wet toothpaste. Is that too thick?

I really appreciate all of your help, thank you.