Tuckpointing 1890 Home

les digits

I have to deal with tuckpointing some portions of my 1890 home.
I have been informed that the original is lime mortar, & most of the joints are about 3/16".
I have seen many terrible tuck point jobs that resulted in destroying the original appearance of a structure.
I've had three pros look at the job, & they are reluctant to use lime mortar. None has even returned with an estimate.
When all that I have read indicates that using anything other than lime mortar is an absolute no-no, why are these "pros" telling me that it is not necessary to repoint with lime mortar?

I am getting fed up with the process of dealing with masonry contractors, & have decided to start repointing myself.
I have worked in construction trades all my life, but stacking bricks is one area where my experience is marginal, at best.

After getting a perfect color match (white), the major stumbling block that I envision is the process of easily filling the tiny voids. It seems that if done by hand, it will be very messy, & I am unknowing re the proper muriatic acid cleanup concentration & timing.
I have a pressure washer, & have used muriatic, & other acids in the past.

The brick is high fired, red, & smooth surfaced, but there is some porosity where mortar will hang up.

I have maybe 800 square feet of pointing to do. I am considering buying a QUIKPOINT® mortar gun.
A bakers bag would be cheaper, but kind of tiring on the hands I would assume.

I will start on the least conspicuous area of the house & hope to learn as I go, but am looking for pointers (pun intended) from a pro.

Your advice would be appreciated, as well as links to any websites where pitfalls are discussed would be helpful.

Thanks

6stringmason

If possible could you post some pictures. I would like to see how bad the joints are. Also did you grind them out and go back and brush or blow air in them to clean them good. If you grind the joints out to at least 1/2" to 5/8" deep you can refill them with whatever type of material you want really. Keep mind the joints still have to maintain their own weightload of course. And I dont know why they wouldnt use lime mortar again. Lime is the difference between what people use to lay bricks vs. a driveway or sidewalk. Portland cement is supposed to have an aggragrate added to it like pea stone or gravel. Lime gives the mortar the stickiness it needs to be able to stick to stone, brick, or other joints even.

You could also use a type S mortar. It has additives in it the strengthen the dry product and also sets up faster. We use that for alot of stone work so we can lay more in a day without worrying about fallout.

As far as what I would use to get the mortar in. I guess thats personal preferance really. I would use a grout bag. Cut the hole open on the end a little bit so you dont have to squeeze as hard. For someone who is not used to it though it will feel like your forearms will fall of after probably 15 minutes. Just remember to twist from the top down and let the twisting action do the work of gettin the mortar out. Don't squeeze the bag in the middle. That doesn't work too well.

As far as cleaning goes that is really a trial and error method in my opinion. Always start in the least conspicuous place to see how the brick react it to it. And dont use a heavy mix at first. Muriatic acid is sold in a standardized concentration of 31.45% acid and 68.55% inert ingredients, primarily water.(last statement copied off this sitehttp://www.naturalhandyman.com/iip/infxtra/infmur.shtm)
Good luck. Let us know how it turns out.

K2

I don't know what "lime mortar" is but we used to mix "white portland" and lime to make mortar. Good strength and a nice white color. RT

jvcstone

been holding on to this article about various mortar mixes for a while.
Enjoy
From NPS's Preservation Brief 2: Repointing Mortar Joints in Historic Masonry Buildings. Mortar Type and Mix

Mortars for repointing projects, especially those involving historic buildings, typically are custom mixed in order to ensure the proper physical and visual qualities. These materials can be combined in varying proportions to create a mortar with the desired performance and durability. The actual specification of a particular mortar type should take into consideration all of the factors affecting the life of the building including: current site conditions, present condition of the masonry, function of the new mortar, degree of weather exposure, and skill of the mason. Thus, no two repointing projects are exactly the same. Modern materials specified for use in repointing mortar should conform to specifications of the American Society for Testing and Materials (ASTM) or comparable federal specifications, and the resulting mortar should conform to ASTM C 270, Mortar for Unit Masonry.

Specifying the proportions for the repointing mortar for a specific job is not as difficult as it might seem. Five mortar types, each with a corresponding recommended mix, have been established by ASTM to distinguish high strength mortar from soft flexible mortars. The ASTM designated them in decreasing order of approximate general strength as Type M (2,500 psi), Type S (1,800 psi), Type N (750 psi), Type O (350 psi) and Type K (75 psi). (The letters identifying the types are from the words MASON WORK using every other letter.) Type K has the highest lime content of the mixes that contain portland cement, although it is seldom used today, except for some historic preservation projects. The designation "L" in the accompanying chart identifies a straight lime and sand mix. Specifying the appropriate ASTM mortar by proportion of ingredients, will ensure the desired physical properties. Unless specified otherwise, measurements or proportions for mortar mixes are always given in the following order: cement-lime-sand. Thus, a Type K mix, for example, would be referred to as 1-3-10, or 1 part cement to 3 parts lime to 10 parts sand. Other requirements to create the desired visual qualities should be included in the specifications.

The strength of a mortar can vary. If mixed with higher amounts of portland cement, a harder mortar is obtained. The more lime that is added, the softer and more plastic the mortar becomes, increasing its workability. A mortar strong in compressive strength might be desirable for a hard stone (such as granite) pier holding up a bridge deck, whereas a softer, more permeable lime mortar would be preferable for a historic wall of soft brick. Masonry deterioration caused by salt deposition results when the mortar is less permeable than the masonry unit. A strong mortar is still more permeable than hard, dense stone. However, in a wall constructed of soft bricks where the masonry unit itself has a relatively high permeability or vapor transmission rate, a soft, high lime mortar is necessary to retain sufficient permeability.

Constituents of Mortar

Sand: Sand is the largest constituent of mortar and the material that gives mortar its characteristic color and texture. When viewed under a magnifying glass or low-power binocular microscope, particles of sand generally have either rounded edges, such as found in beach or river sand, or sharp, angular edges, found in crushed or manufactured sand. For repointing mortar, rounded or natural sand is preferred for two reasons. First, it is usually similar to the sand in the historic mortar, thus providing a better visual match. Second, it has better "working" qualities or plasticity and can thus be forced into the joint more easily, forming a good contact with the historic mortar and the surface of the bricks. Although manufactured sand is frequently the only type readily available, it is worth the search to locate a sufficient quantity of rounded or natural saltfree sand for repointing.

Lime or Portland Cement: The two commonly used binders for mortar are lime and portland cement. Of the two, lime produces a mortar that meets nearly all the requirements for a good mortar for historic buildings, while portland cement produces a mortar that does not perform as well. High lime mortar is soft, porous, and changes little in volume during temperature fluctuations. In addition, lime mortar is slightly water soluble and thus is able to reseal any hairline cracks that may develop during the life of the mortar. Portland cement, on the other hand, can be extremely hard, is resistant to movement of water, shrinks upon setting, and undergoes relatively large thermal movements. The use of a high lime mortar, therefore, is recommended for nearly all repointing projects. However, white portland cement can be substituted for up to 20 percent of the lime (ex. 1 part cement to 4 parts lime). This will usually improve workability or plasticity without adversely affecting the desirable qualities of the lime mortar. Plasticity is important to ensure a good bond between the new mortar, the historic mortar, and the brick.

Water: Water should be clean and relatively free of salts or acids.

Historic Additives: In addition to the color of the sand, the texture of the mortar is of critical importance in duplicating historic mortar. While modern mortars are finely ground and present a uniform texture and color, historic mortars were not as well ground. They may contain lumps of oyster shell, partially burned lime, animal hair, or particles of clay. The visual characteristics of these additives should be duplicated through the use of similar materials in the repointing mortar.

Squeezing a grout bag gets old in a hurry, and in my experience, the mix has to be too wet. I prefer to use the back side of my trowel for the mud and a tuck pointer. No fuss -no mess.

JVC

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les digits

6stringmason,
I'll snap some pics tomorrow & post them.
Basically, the brickwork is in pretty good shape on most of the house. The exceptions are where downspout / gutter failure led to significant mortar washout. A few vertical joints are totally devoid of mortar. Many joints in these areas look OK, but the mortar has been compromised, so removal will be required.

I have not begun to remove the bad mortar. I am doing my research at this point & really appreciate your input.
I was thinking that pressure washing might be the best final step in the removal / cleanout process. Just for dust removal, & to keep the new mortar from drying too rapidly. Is that notion sound?
I remember, years ago, soaking soft brick in buckets to prevent the soft brick from sucking too much water from the mortar.

JVC,
Thanks soooo much for that Preservation Brief. I recently spent an hour googling for it to no avail.
Also you say:
"I prefer to use the back side of my trowel for the mud and a tuck pointer. No fuss -no mess."
Ya, but I'm a wood butcher, & I think your skills exceed that which I will be able to achieve on this one job.
I envision more mortar on the ground than in the brick!

Once again,THANKS!

6stringmason

LOL! Wood Butcher. I would advise against pressure washing the work area if some of the brick are as bad as you say in spots. A pressure washer could really mess up some of the brick if your not careful and dont have good aim. It is possible you could blow the face off of brick. If you want to wash it I suggest a hose and an adjustable psi nozzle to remove the fine dust.

jvcstone

I concure with the no to pressure washing suggestion. I've seen more masonry damaged by indicriminant pressure washing than from most anything else.
JVC

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www.jvcstoneworks.com

red_cedar

I have been to seminars of historic restoration. They always talked about useing the lime mortars. You could always take a sample and have it anylized to make it pretty much of a match.
I am not a mason but a roofer by trade and have done my share of tuckpointing. I use water to clean the joints out after the mortar is removed. Have not worked with lime mortars though.

Teetorbilt

You may want to check out the This Old House site. I remember them doing this not too long ago and discussing mixes. They also have a Q&A section that may help. I revere older homes but am a fan of the future.

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les digits

Hi again guys,

Upon closer examination, I see that most of failed vertical joints are abnormally (for this house) wide.

See some photos here:
http://photobucket.com/albums/a117/Les_Digits/

A month ago I pressure washed some areas after spraying on Diedrich 101 masonry restorer. The product is absolutely perfect for this job. It easily removes paint spatter & 100-year-old grime.
http://www.diedrichtechnologies.com/page14.html

Diedrich 505 (paint remover) was used to loosen up heavy latex paint that was slopped all over the brick.

We have 10 years experience with the pressure washer, & are being careful about damaging the surface of the brick.
A low-pressure tip is being used.

The next step:
I am going to remove some mortar, crush it up, mix & let it settle in water. I have read that this will divulge the original %'s of the original mix.
Then I'll be off the local masonry supply.

Thanks a bunch for sharing your knowledge with me.

Earl

jvcstone

Earl, I am curious about your mention of the failed joints being wider than normal. Do they appear to be roughly in a vertical line, zig-zaging up the wall, and getting wider as they get higher? Or does it appear that the masons streched the brick with wider joints in some places? The first situation is an indication of foundation movement and should be addressed also.
JVC

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www.jvcstoneworks.com

les digits

JVC,
Thanks for your wisdom.
Re:"Or does it appear that the masons streched the brick with wider joints in some places?

The original brickies did stretch the vertical joints that eventually failed due to water penetration.The wide vertical joints, where they occur, are the same width top to bottom, & are unassociated with foundation movement.

I'm guessing that the wider joints are more subject to freeze/ thaw damage, & thus had a shorter life than the normal mortar joints.

Earl

jvcstone

That's good to hear. One less thing to worry about. In my part of the world we have a lot of expansive clay soil, and foundation distress is the first thing I look for when there are open head joints.
Good luck with your repointing job.
JVC

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www.jvcstoneworks.com

JB Mohler

Sometimes on small repoint jobs like that, where the mortar is kinda white-ish, i would use the saw and cut and cut and cut some lime stone.

I used Dragon mortar for those jobs, its not grey, kinda tan, then i would smudge the stone dust over the wet mortar, and joint it.

No matter what you do though, it will look fixed one way or the other.

Calureview

Its been a while since this thread was posted. How did your project turn out?

lukachuki

May not be around anymore....A lot of people are one thread wonders!

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Calureview

everybody gave him all this good info and we get no follow up? this is like buying a book that has no ending.

drasylum

You will find that most masons are NOT familiar with lime mortar or lime putty, what they fail to tell you and its due to ignorance is that you can ruin the brick if you do not use the proper materials. I wish that it was just that easy to put any mortar in when you are repointing, but each material has a different compression which if not used properly can cause some severe problems. Lime putty application is a fairly easy deal, there are a couple of good videos online (just google on Utube) that describe ther proper process. We are in the process of restoring a historical building as of now using lime putty so we do know what we are talking about

Rock Headed

Okay I'll just hijack this thread--everyone relax, noone gets hurt.

I've been wanting to get into using lime mortar--not nessesarily for historic work, but for also for some new jobs as well.

So far google has only helped a little.

I've taken hydrated lime, same stuff I mix with portland and sand to make typical cements, mixed it with sand and water and came up with a decent mix that held together well and stuck them stones together.

Do I NEED to make lime putty first?

Today what I am going to go do is to mix up half a bag of hydrated lime with water, pour a couple inches of water on top of the mix, put a lid on it, come back in 2 weeks and skim off the water. At this point I should have some decent lime putty and I am ready to add two parts concrete sand (as I understand it you don't want to use the real fine sand that we are used to using for mortar) and the I should have some quality lime mortar.

Any hot tips, save me time and/or money, any sweet resources anyone can point me torwards?

Thanks.

artisanstone

Most of what I know about it is from researching. I have used what would be considered a Type O mortar. 2 parts hydrated lime to 1 part white portland. I did premix and slake the lime overnight. The portland helps give it an initial set, and can affect the reaction, making the lime hydraulic.

From what I understand, the bagged hydrated lime will never have the same properties as putty made from quicklime. In areas without access to quicklime, the mix I described is often used.

It gets more complex than this. Lime mortar performance depends on the mineral composition of the parent material. High quality lime is fairly available in Europe, but is more difficult to source here. Curing properly is also much more important for lime mortars than for high portland mortars. The work should not be allowed to dry out for a month or so. Some lime mortars may take years to fully set in the center of the wall. This is because lime mortars set by carbonation which requires air.

Patrick Macafee is an Irish stonemason who has written a lot about lime mortars. He has several books out. There is also Virginia lime works?? A U.S. company that supplies the restoration industry.

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