[tom_poconos]

Hi there! I need to make some repairs to some loose bricks in an old non-structural interior wall - it's at least 100 years old. Many of the bricks have extensive spalling, while many are still ship-shape. As I understand it I need to use an old mortar mix as a modern one will cause the soft bricks to implode.

The mix suggestions I've found online vary. Some mixes call for just lime and sand, others call for some cement. Then there is no consensus on ratios.

1. Can someone chime in on the correct ratio of lime, sand and water?
2. Should any portland cement be added?
3. Is "Hydrated Lime" what I want?
4. Is the sand you would put in a kid's sandpit sufficient, or is there a special sand I need?
5. What is the ideal consistency? I also found no consensus on this.

Sorry for the multiple questions. Thanks in advance for any help!

 

[ClarenceBauer]

Hi there! I need to make some repairs to some loose bricks in an old non-structural interior wall - it's at least 100 years old. Many of the bricks have extensive spalling, while many are still ship-shape. As I understand it I need to use an old mortar mix as a modern one will cause the soft bricks to implode.

The mix suggestions I've found online vary. Some mixes call for just lime and sand, others call for some cement. Then there is no consensus on ratios.

1. Can someone chime in on the correct ratio of lime, sand and water?
2. Should any portland cement be added?
3. Is "Hydrated Lime" what I want?
4. Is the sand you would put in a kid's sandpit sufficient, or is there a special sand I need?
5. What is the ideal consistency? I also found no consensus on this.

Sorry for the multiple questions. Thanks in advance for any help!

There are a few mix's you could use.
First look @ Preservation Briefs # 2 this brief will have info you can use.
Check page # 13 Mortar types ( measured by volume's ) for soft brick it states to use a type "K" 1 cement use "White" 3 Hydrated Lime & 10 - 12 Sand.
You may be able to find this on line " An Introductory Guide to the Repair of Charleston's Historic Masonry and Wood Buildings. by George Fore.
He uses a Mortar that is interchangeable for repointing & Stucco. If you break his formula down you can use 3/4 parts White Cement 3 - 4 parts Type "S" Lime & 9 - 14 parts Sand. you will find this on page # 43.
Preservation Briefs # 22 also has a Soft Brick Mortar formula 5 Gallons Hydrated Lime 10 Gallons sand 1 Quart White Portland Cement page # 10.
Also look @ using a Natural Hydraulic Lime use NHL 2 PIS about 250 350 lbs.
NHL 3.5 will have a PSI of 750.
If you are on the South East Coast I would recommend that you use A.W. Cooks Mason Work Historical Mix this is a premix that just requires adding water PSI s 250. I have used " my guess over 500 bags " no problems.
If you research www.mc2-ice.com "Estimators' Reference it will give you all the formula's for ASTM mixes & PSI rating "TAKE NOTE OF PAGE # 7 of 7"

 

[ClarenceBauer]

My brain just activated you are in Philly.
Check Lime Works US
P.O. Box 151
Milford Square, PA. 18935
PH# 215-536-6706
e-mail [email protected]

 

[tom_poconos]

My brain just activated you are in Philly.
Check Lime Works US
P.O. Box 151
Milford Square, PA. 18935
PH# 215-536-6706
e-mail [email protected]

Thanks a lot. I found this mortar on Limeworks. Would that be sufficient for my purposes? It's not Type K as you mentioned (it's Type G - coarse). Unfortunately at $30/bag it's at least quadruple the cost of mixing the components myself plus a 2-hr round trip to Telford.

I'm leaning towards your suggestion of:

• 1 part White cement
• 3 parts Hydrated Lime
• 10-12 parts sand

These components are inexpensive and easy to source locally.

 

[ClarenceBauer]

Thanks a lot. I found this mortar on Limeworks. Would that be sufficient for my purposes? It's not Type K as you mentioned (it's Type G - coarse). Unfortunately at $30/bag it's at least quadruple the cost of mixing the components myself plus a 2-hr round trip to Telford.

I'm leaning towards your suggestion of:

• 1 part White cement
• 3 parts Hydrated Lime
• 10-12 parts sand

These components are inexpensive and easy to source locally.

The 1-3-10 will be OK the PSI maybe a little high you could cut the White Cement down to 1/2 part & it should lower the PSI. Are your brick an orange color?

 

[tom_poconos]

The 1-3-10 will be OK the PSI maybe a little high you could cut the White Cement down to 1/2 part & it should lower the PSI. Are your brick an orange color?

Yep, the bricks are an orange/brown. I'm actually having trouble finding white portland cement. There are many other cements but they're grey, brown or their color is not specified. White seems to be scarce or unavailable at local hardware stores.

 

[ClarenceBauer]

For that type brick use the lower PSI mortar.
As for White Cement check the local brick yard sales office they should be able to help you. Maybe the local landscape company will have it or know where to get it.

 

[SPS-1]

Clarence, --- care to venture a guess on how OP might get spalling on interior bricks ?

 

[ClarenceBauer]

Clarence, --- care to venture a guess on how OP might get spalling on interior bricks ?

Could be that someone had repointed earlier & used the wrong mortar?
Could have been a water leak over a long period of time causing the movement of salts to delaminate the face of the soft Brick " effervescence ".
Was the Brick covered with something at some time like plaster / Cement?

 

[stuart44]

Another cause is that on older properties the poorer quality bricks from the burn tended to be used on internal walls.
In the UK in the 1980's there was a fashion to use old reclaimed bricks for the face work on Newbuilds. However after a few years many were starting to spall, so nowadays new bricks have a frost and salt rating.

 

[tom_poconos]

Was the Brick covered with something at some time like plaster / Cement?

No plaster on the brick, but there was a lathe and plaster wall in front of it on furring strips. Unfortunately for me there was also wood paneling and then drywall on top of that - 3 layers of wall I had to rip out :vs_cry:

Another cause is that on older properties the poorer quality bricks from the burn tended to be used on internal walls.

This is what I was told too - back in the day the apprentices were tasked with interior walls and they often used a lower quality brick.

I don't believe there was any major water penetration into the interior wall, as I see no evidence of water damage to the joist above it or the lathe that I ripped out in that area, so I suspect this particular interior wall was just constructed with poorly fired bricks. An image is attached of the room - you can see to the right the other wall has virtually no spalled bricks at all.

 

[ClarenceBauer]

No plaster on the brick, but there was a lathe and plaster wall in front of it on furring strips. Unfortunately for me there was also wood paneling and then drywall on top of that - 3 layers of wall I had to rip out :vs_cry:



This is what I was told too - back in the day the apprentices were tasked with interior walls and they often used a lower quality brick.

I don't believe there was any major water penetration into the interior wall, as I see no evidence of water damage to the joist above it or the lathe that I ripped out in that area, so I suspect this particular interior wall was just constructed with poorly fired bricks. An image is attached of the room - you can see to the right the other wall has virtually no spalled bricks at all.

Looks like there was a moisture migration problem in that brick wall with the soft brick. The cause was the layers of plaster covered with plywood & drywall. What do you intend to do about the bricks that have the brick face failure?

 

[tom_poconos]

What do you intend to do about the bricks that have the brick face failure?

I'd like to secure any loose bricks I find using a mortar bag and tuck point trowel, then paint it white. I might stucco some areas that have heavy spalling. Do you see any issues with this approach? Also, would you use a different mortar mix for the stucco, versus the tuck point repairs?

P.S my apologies in advance if you think I'm ruining a beautiful old brick wall by painting it... it's just there's so much brick dust you can't go near it without getting a huge orange smudge on your clothes. I have cleaned it with a wire brush and will clean it again but I'm afraid it will always be producing too much dust.

 

[ClarenceBauer]

I'd like to secure any loose bricks I find using a mortar bag and tuck point trowel, then paint it white. I might stucco some areas that have heavy spalling. Do you see any issues with this approach? Also, would you use a different mortar mix for the stucco, versus the tuck point repairs?

P.S my apologies in advance if you think I'm ruining a beautiful old brick wall by painting it... it's just there's so much brick dust you can't go near it without getting a huge orange smudge on your clothes. I have cleaned it with a wire brush and will clean it again but I'm afraid it will always be producing too much dust.

If leaving the existing brick in place I would use one of the following products to consolidate the brick.
(1) ProSoCo H Stone Strengthener or OH Stone Strengthener.
ProSoCo Ph # MD.410-321-7597 NJ 908-754-4410

(2) Keim Fixativ
Keim Ph # 866-906-5346
I kind of like the Keim product.
Remove the existing mortar to a depth of 1 & 1/2 inch repoint in two lifts of 3/4 inches each make sure you moisture cure it.
Than apply the selected product to consolidate the soft brick this should also keep it from dusting.
As for applying Stucco over the brick it will not adhere very well due to the dusting will still occur behind the Stucco causing delamination.
Even if you Stucco it you will need to consolidate the brick.
If Stucco is selected you should use a weaker mortar for the Stucco.
Say you use the 1-3-10 mix you would reduce the cement or increase the sand. Just keep in mind as you build out with mortar it should get weaker as you build it outward.

 

[tom_poconos]

Thanks, that makes sense. I guess I could forget the stucco entirely and just do the silicate coat in white after repointing the loose bricks.

I kind of like the Keim product.

Did some searching for Keim Fixativ and it seems very scarce, at least online. Do you have any experience with Ecologic Potassium Silicate Paint? Limeworks is about an hour from me. Is it a similar product from what you can tell? Thanks a lot.

 

[ClarenceBauer]

Thanks, that makes sense. I guess I could forget the stucco entirely and just do the silicate coat in white after repointing the loose bricks.



Did some searching for Keim Fixativ and it seems very scarce, at least online. Do you have any experience with Ecologic Potassium Silicate Paint? Limeworks is about an hour from me. Is it a similar product from what you can tell? Thanks a lot.

NO the Ecologic product will NOT penetrate the brick & consolidate it will only be a surface treatment.
You have to use a product that the bricks will absorb & cause it to consolidate the soft material.
You will have to contact Keim to check on the nearest dealer.
Also you can check with Cathedral Stone in MD. Ph # 800-684-0901 & ask if they have a consolidate that will work on brick. I have used their mortar & Grouts all very good products.

 

[tom_poconos]

NO the Ecologic product will NOT penetrate the brick & consolidate it will only be a surface treatment.
You have to use a product that the bricks will absorb & cause it to consolidate the soft material.

You mentioned the Keim product will consolidate with the soft brick material. I was wondering, will this make the interior wall surface harder than the brick or act as a moisture barrier? If so, could this then lead to further spalling below the consolidated surface?

 

[ClarenceBauer]

The Keim product should be fine no problems.