Lime Mortar Repointing: The Basic Techniques for Restoring Historic Brick Homes
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- เผยแพร่เมื่อ 13 ก.ค. 2009
- Preservation Works Ltd. is a historically appropriate masonry restoration company that specializes in the repair of lime mortar buildings. We are producing a series of videos to visually explain the way lime mortar repointing is done and why it should be done (and why it costs a bit more to do the repair correctly the first time). Lime mortar is the material used in traditional building before the invention on Portland cement and the modern building industry. Buildings originally built with lime mortar should be repaired with lime mortar.
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Thanks for the very clear and crisp information on lime mortar repointing!
Thanks for the compliment. I never had any cracking problems with "slightly" wet lime mortar. It is more important to have a damp substrata and to keep the mortar from drying out too quickly, this is the root of most cracking in my experience. The joints were 3/8" not 5/8" and were cut back 3/4 to 1" or a depth of at least twice the height as per historic restoration recommendations detailed in Preservation Brief 2- which is where most architects get their knowledge of historic restoration.
Excellent and informative video - thanks for posting it.
Fantastic video and very educational. Exactly what i needed thank you.
Glad it was helpful!
a few tidbits, always point from top to bottom! saturate the wall first! Lastly, lime mortars need to be kneaded, as the compression forces the lime molecular into the aggregate. Stand time before using, as well as specific water and aggregate amounts must be adhered to. this can mean the joint lasting 10 years or 50 years is properly done. thanks
Very useful information, thank you.
This is very educational. We have four interior exposed brick fireplaces in our 100 year old home in New Orleans. We are DIY because of budget constraints. I’m counting on this series to direct the work. Thank you.
Excellent information!
Thanks for watching!
Found this video very useful 👌
Thank you for that information on hardness of mortar and spalling I was always told that type N is sufficient for Brick. But type S is to hard? In the restoration process of an old building I would definitely use the lime mortar. I am a chimney Builder and I come across chimneys all the time with spalling brick sometimes 90% of the chimney is spalling. I always see chimneys that are hundred years old or so last forever with no spalling but newer Masonry gives out a lot quicker. Why the change from lime mortar to cementouse?
What would you charge for a wall like that in your video?
Interested to know how much easy the mortar needs to come off if I take a flat head screw driver and drag it hard on the mortar, if I'm able to get out a few small grains of mortar is the mortar considered weak and crumbing? Thanks in advance. In your video just by touching the mortar, it all comes off, which is too easy.
No, not generally if it's just a few grains but it depends what type of mortar it is. Cement mortar and lime mortars age differently.
@@PreservationWorks thanks for your feedback
I have a question. I'm about to have to do this on an older home. The mortar on it has a red hue like it has red clay mixed in it. Do you know how to recreate that look?
Are you all going to make another video? I hope so.
please tell me exactly what the ratio and proportion of your mortar is. thanks
Hello sir can u tell me please how to mix the lime.? Thx.
Do you guys put in dpc 's in your brickwork 150mm above ground? Im from the uk and i was wondering if you guys did. Also do you get rising damp?
Over here on older mass wall masonry, a damp stop is applied at the watershelf, approximately 16" above grade. Newer vaneer walls have a thorough wall flashing at the base, preventing rising damp in the process.
Lime mortar tuck pointing is more complex than just a standard combo mix of lime, sand and such. To properly tuck point, testing of the mortar of the specific structure must be done. When this is done, then you will know exactly what ratio of mix you would need for a specific application. If you don't have your mortar tested than simply following some standard mixture could do more damage than Portland cement. Always check references of a restoration company before hiring. If they are not willing to have your mortar tested to find out it's base ingredient combo then they are not worth hiring. Testing is simple, but it's the waiting for results that is key. The restoration company sends out the samples and then they wait. A series of tests are done on the mortar and when finished, you are informed exactly what is in your specific mortar and what the specific ratio of ingredients to use to match your original mortar exactly. Demand the best folks. If you are going to invest in repointing your 100 year old residence, then the least you can do is DO IT RIGHT.
Roberta Kratochwil You appear to be using tuckpointing interchangeably with repointing. If so, this is incorrect. Tuckpointing is a specialized pointing technique done to increase the appearance of uniformity of the mortar joint (as well as conceal irregular mortar joints necessitated by irregularly-sized bricks and / or stones). More specifically, it creates the illusion that the mortar joint is much smaller than it actually is and thereby suggests that the wall is built of expensive, precisely-formed bricks.
wher would you get your mortar test done ???
What did you do about the broken/spalled bricks in this wall please? for example, did you replace them all, some or none? If you left some how did you decide and did you give them any treatment? Thank you for great video!
Hi, this is my question aswell? Thanks :)
@@charlottewarburton5488 since this time I have started repointing the bricks on my house. I intend on replacing a lot of them, however, I am also going to try a bit of 'refacing' where they are not too bad. i.e. using brick dust (I have a lot!) and lime mortar to great a new facing to the brick. Not tried it yet, but thought you might be interest.
Hi. If anyone can answer this question it would be greatly appreciated. I have exposed a brick chimney breast in a bedroom, its nonfunctional, just a feature. I used portland cement to repoint it. Will i have trouble with this in the future? Also if I was to seal it what material should I use? Thanks.
It'll probably be ok since it doesn't get wet and freeze
Hi we are building a new house with bricks but since our old house was also made of bricks we have decided to use those old bricks for all the inner walls and purchased the new bricks for all the outer walls. It is a two storey building. Is there any trouble for reusing the old bricks. Please kindly reply
Shouldn't be a problem if the old bricks are cleaned properly and in good shape. If the old bricks have mortar that needs to be chipped off, it can be a time-consuming process to be able to reuse them. Hope this helps! If you have more questions and require a faster response, please contact us directly at info@preservationworks.us
@@PreservationWorks Thanks for your reply.
Hello!
I have an old room where i removed the old plaster on the inside, because it was damaged, mold etc., therefore exposing the brick work with it's old lime mortar. The mortar now is turning into a sand dust if I touch it, so, I think it needs to be removed to a degree and repointed . For rendering the wall I will use cement based plaster, instead of lime, because lime is pretty rare in my zone, cement is almost the one and only choice for constructions. Do I need to repoint the old mortar on the inside before I apply the new cement based plaster, or should I let it the way it is? And is it ok if I repoint it with cement mortar? I am speaking only about the plaster on the inside of the room, heated zone, not the outside of the house.
Thanks for your message.
Please feel free to contact me directly at info@preservationworks.us, but to give you a partial response:
There should not be mold on lime based plaster; how old is the building?
If lime mortar is turning to dust, it should be removed.
I wouldn't recommend using a less-permeable, cement based mortar; you could get high calcium lime or type S lime which can both be turned into lime putty.
Also, we have natural Hydraulic lime for sale at www.preservationworks.us
Again, reach out to us directly for more info!
What is a mixing ratio for lime mortar? Some sites suggest the sand, portland cement and lime are 5:1:1 whilst some suggest 8:1:3 respectively. What ratio is correct for repointing? Thanks
I'm 9 years late, but the historical mis mix would be 6 sand, 1 Portland, 1 limestone
5 building sand
2 sharp sand
2 lime
For bricks 5:2 or 5:1:1 using hydrated lime an cement
How much time does it take for the newly applied lime mortar to cure?
Natural Hydraulic lime generally begins to set somewhere between 4-8 hours after mixing, and it reaches its minimum compressive strength in 28 days.
@@PreservationWorks thanks
The mortar is not expendable like the tyre of a car as you say. If too much of the mortar deteriorates the wall will fail. You can only repair the mortar on the outer edge, the mortar behind this must hold the wall for the walls entire life. So how much mortar does a wall need, will a wall fall down if 2 inches of mortar are missing??
if mortar is too wet (especially lime) you get more shrinkage cracks
1:39, how long can these building last?
inlovewithi longer than any new ones built today back then they built buildings to last if properly maintained it could last forever
I looked up this drawing from 1885 on Google street view, since it is a representation of what the artist was viewing, and to my surprised one of the buildings is still up. upload.wikimedia.org/wikipedia/commons/8/84/Broadway-1885-APL.jpeg
Like Oldhandyluke said- if properly maintained, forever
Yes this is true but I have found that the worry is generally unjustified. "Slightly" wetter mortar is easier to work with and less physically demanding on the applicator. The wall in this video had no shrinkage cracking for example. A greater problem concerning cracks is allowing the mortar to dry out too quickly either because the wall was not sufficiently wet before installation or because it was not protected from sun and wind after installation.
PreservationWorks Rob... please call me back. I need you to come do this job... I know your busy, but I'll even pay extra. Tara was supposed to contact me for a credit case deposit, but I never heard from her.
Why don't you do the perps first
Lime mortar is very complex. Heinrich Burchartz has tested hundreds of lime mortar mixtures under lots of conditions. Generally the quality depends on many factors like amount of carbon dioxide available for reaction, sand used, temperature, humidity, etc. There is no general rule. Lime mortar must be manufactured to suite the individual situation. It could take months to find the right mix for the given application.
From a distant eye, I would think he is in the NHL12 range.
v interesting video thank you i did find the music unnecessary and distracting though. maybe birds cheeping would have been nicer
Noted! And thanks for watching!
I have that bird in my yard....
use a pointing trowel much quicker
The only way of learning how to build properly is by reading the comments section of youtube.
Hydraulic lime? I wouldnt use hydraulic lime. It's not about how complicated it is to work with non-hydraulic lime. It's about how often you want to repeat the repairs. Hydraulic lime is falling off after 4 to 10 years. Non-hydraulic lime maybe after 150 to 300 years :) The more it rains on it the longer it will last. In the old days there was no hydraulic lime but those buildings still exist - in contrast to those build with our more modern obsolescence-designed pseudo-lime products.
spalling
sorry fell a zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
If your building is built with like. Replace with lime. Not rocket science
a few tidbits, always point from top to bottom! saturate the wall first! Lastly, lime mortars need to be kneaded, as the compression forces the lime molecular into the aggregate. Stand time before using, as well as specific water and aggregate amounts must be adhered to. this can mean the joint lasting 10 years or 50 years is properly done. thanks