Does German Schmear Need to Be Sealed?

Key Takeaways:

Sealing German schmear provides an extra layer of protection but is not essential for most projects.
The mortar used in German schmear is similar to the mortar between bricks so no further sealing is needed.
Some recommend sealing after applying joint compound to prevent wiping off.
Consulting a professional can ensure proper sealing to prevent cracking and resolve underlying issues.
Factors like climate and quality of bricks should be considered when deciding on sealing.

What is German Schmear and How is it Applied to Brick?

German schmear is a traditional masonry technique that gives brick walls a unique, rustic whitewashed appearance. It involves using a mortar or cement-based material to create a thin layer of plaster on the brick façade. The plaster is then partially wiped or scraped off to reveal hints of the underlying brick color and texture. This softened, aged look is often desirable on historic homes or in cottage-style gardens.

To apply a German schmear finish, the brick surface is first dampened. A thin layer of mortar, Type N or Type S, is then troweled onto the bricks. The mortar is allowed to partially set up, then a wood float or trowel is used to scrape and wipe away some of the mortar to expose brick details. German schmear is typically 1/8 to 1/4 inches thick. It clings to the brick surface and mortar joints but reveals glimpses of the brick face and shape.

Does German Schmear Need to Be Sealed for Protection?

When deciding on sealing a German schmear finish, there are a few considerations. In general, sealing is not strictly necessary but can provide extra protection and durability in some situations.

Since German schmear is created with a mortar material very similar to the mortar used between the brick courses, the schmear has inherent water resistance and durability like the wall itself. The plaster finish chemically bonds to the masonry surface.

A study by the International Journal of Adhesion and Adhesives found that cement-based mortars strongly adhere due to the formation of hydration products that interact with brick. So the schmear gains natural strength and resilience without needing a sealant.

However, factors like exposure to weather, quality of the brick, and desired longevity can make sealing prudent.

Sealing is more critical if the schmear will be exposed to heavy rain, frequent drying/wetting cycles, freezing temperatures, or other harsh environmental factors. Adding a breathable sealer provides extra protection against moisture damage, mildew, and efflorescence.

If the brick is low-quality, porous, or damaged, sealing the schmear provides a sound barrier against moisture intrusion into the wall. It also helps prevent further cracking or spalling issues.

For schmear finishes built to last decades without refurbishing, applying a sealant ensures maximum durability and prevents wear.

So for many residential or commercial projects, sealing German schmear provides worthwhile insurance against damage and deterioration, though it is not absolutely necessary in ideal conditions.

What is the Best Process for Sealing a German Schmear Finish?

To properly seal a German schmear finish, it is important to follow product specifications for application and drying time. But the general process is:

Ensure the schmear has dried completely, usually 10-14 days after application.
Clean the surface thoroughly to remove any dust, efflorescence, or debris that could block penetration.
Apply the sealer evenly according to instructions, using a sprayer, paintbrush, or roller.
Allow the recommended drying time based on humidity and temperature. Apply additional coats if needed.
Confirm that the sealer has adequately penetrated the schmear and beaded on the surface.
Avoid heavy traffic or contact with the wall for 2-3 days to allow a full cure.

The best sealers for German schmear are breathable products that offer protection without trapping moisture. Top choices are silane or siloxane-based masonry sealers that penetrate well and handle alkalinity.

According to testing by the National Concrete Masonry Association, siloxane sealers are able to penetrate German schmear plaster and brick while allowing water vapor transmission. Look for products rated for masonry, concrete, stucco, or brick.

Should German Schmear Be Sealed Right After Application?

There is some debate around whether to seal German schmear immediately versus waiting weeks for it to fully cure. Here are considerations around the timing:

Sealing right away seals the surface before exposure to weather but doesn’t allow full drying. Trapped moisture can cause whitish deposits on the surface. The schmear may still be vulnerable to cracking or chipping.
Waiting 2-4 weeks allows mortar to fully set up and finish drying. But the longer the schmear is exposed before sealing, the more chance for efflorescence or damage.
Optimal timing is 10-14 days after application. This allows initial drying to occur but seals the surface before major exposure or weathering. The schmear has had time to chemically bond to the brickwork.

In general, sealers adhere best if applied 1-2 weeks after the schmear, when the surface is sound but not too aged. Follow the product instructions for recommended timing.

Proper curing is also critical before sealing. Avoid sealing if temperatures have been consistently below 50 degrees F which slows curing. Test moisture levels in a few areas to ensure the schmear is dry enough to accept a sealer.

What Kind of Sealer Should be Used on German Schmear?

When selecting a sealer for German schmear plaster, look for a product that offers protection without changing the appearance or trapping moisture:

Silane/siloxane sealers provide excellent penetration and breathability. They withstand alkalinity to prevent whitish deposits. These silicone-based sealers are designed for masonry and ideal for schmear.
Acrylic sealers adhere well but may alter surface appearance more than silane/siloxane sealers. Ensure the product is rated for masonry.
Penetrating epoxy sealers offer very robust protection for severe conditions but have limited vapor permeability.
Film-forming sealers like polyurethanes are not recommended for schmear since they can peel, trap moisture, and alter the aged look.

Always check that the manufacturer recommends the sealer for plaster, stucco, concrete, or masonry materials similar to German schmear.

Avoid wax-based sealers which can cause discoloration. Do not use sealers intended only for natural stone.

Test the sealer in an inconspicuous spot to ensure proper penetration and appearance before applying to the entire schmear surface.

How Much Does It Cost to Have German Schmear Sealed Professionally?

Hiring a professional masonry contractor to seal your German schmear finish typically costs $1.50-$3.00 per square foot depending on:

Accessibility – higher for second stories or high surfaces needing equipment.
Labor rates in your region.
Special preparation needed – cleaning, repairs, etc.
Number of sealer coats applied.
Choice of sealer product and coverage rate. More advanced sealers cost more.
Overall size of the project. Bigger square footage lowers price per foot.

So for a typical single story home of 2,000 square feet, expect to invest around $3,000-$6,000 to have a contractor clean, seal, and protect the schmear finish.

Be sure to get an itemized estimate accounting for all necessary preparation, materials, equipment rental, labor hours, and number of visits. Reputable contractors guarantee their sealing work against defects for 1-2 years.

Will Sealing Prevent German Schmear From Rubbing Off Onto Hands?

One concern with German schmear is that the thin plaster finish can rub off on hands or brush onto clothing if not properly sealed. Sealing helps bind the schmear to the masonry and prevents transfer of the coating.

Without sealing, the schmear remains somewhat fragile and powdery while drying and curing. A good sealer penetrates and hardens the surface so the plaster becomes more integral to the wall.

Look for a sealer rated to seal and bind concrete, stucco, mortar, or masonry surfaces. Silane/siloxane sealers soak in well to consolidate the schmear without leaving a film.

Proper application is also key – ensuring full coverage without gaps, drips, or missed areas. Follow manufacturer guidelines for number of coats and drying time between applications.

Test the rubbed surface after sealing to ensure the schmear is no longer coming off on contact. If it still seems powdery or loose, apply another round of sealer for maximum durability.

Will Sealing Prevent Efflorescence From Forming on Schmear?

Efflorescence is a common issue with masonry and cement products like German schmear. It appears as white powdery deposits on the surface. Efflorescence is caused by water soluble salts in the materials that get drawn to the surface and leave behind a whitish chalky residue as they dry.

While schmear without sealer is vulnerable to efflorescence, sealing is an effective preventative measure. The sealer forms a protective barrier that prevents moisture and salts from migrating through the schmear to the surface.

A study by the National Concrete Masonry Association found that silane and siloxane-based sealers were able to significantly reduce efflorescence on brick and mortar surfaces by repelling water penetration.

When sealing to prevent efflorescence, proper preparation is key. First thoroughly clean the schmear with masonry cleaner to remove any existing salts or deposits. Allow to fully dry. Then apply the sealer according to manufacturer instructions to create a water-repellent barrier.

Sealing the schmear shortly after application, before exposure to weather, provides maximum protection against efflorescence. But sealing at any point will help prevent further formation.

Regular maintenance cleaning using a phosphate-free detergent is recommended to remove any salts that might build up on the sealed surface over time. Reapply sealer every 5-10 years for ongoing efflorescence prevention.

Does Sealer Prevent Schmear From Showing Dirt Over Time?

One downside of unsealed schmear is that being cement-based, it can accumulate dirt, grime, and pollutants from the environment over the years. Sealing the finish helps keep it looking clean longer.

Schmear is slightly absorbent and porous until sealed. Dirt and grime are able to lodge in the tiny pores and gradually make the surface appear darkened and dingy. Sealer penetrates the plaster to fill pores and create a protective barrier.

According to the International Journal of Adhesion and Adhesives, silane-based sealers are able to bind cement particles together for improved resistance against soiling.

Proper sealing techniques like ensuring full coverage and adequate drying time between coats maximizes the grime-resistant properties.

Regular gentle cleaning is still recommended for sealed schmear. But the sealer prevents deep-down buildup of dirt and makes maintenance washing easier. Harsh chemical cleaners are less frequently needed.

Over time, sealing helps maintain the pristine whitewashed, rustic look of German schmear by keeping the finish from appearing prematurely aged due to dirt accumulation. Reapply fresh sealer every 5-10 years for optimal grime prevention.

Will Sealing Prevent Schmear From Freezing and Cracking in Winter?

In cold climates, sealing German schmear before winter provides important protection against freeze-thaw damage. When temperatures cycle above and below freezing, unsealed schmear is vulnerable to cracking and spalling as moisture expands and contracts inside the material.

According to the Portland Cement Association, sealers help prevent freeze-thaw damage by limiting the amount of water able to penetrate the cement plaster finish. Silane/siloxane sealers are designed to maintain vapor permeability while repelling liquid water.

When applied properly to the entire schmear surface before cold temps arrive, sealer forms a water-resistant barrier. This keeps the schmear drier during freezing and thawing cycles, reducing internal stresses.

For maximum protection against ice damage, use a coating rated for masonry/concrete and apply 2-3 layers. Allow adequate drying time between coats. Check for any missed spots that could allow moisture intrusion when temperatures fluctuate.

Sealing a few months before winter provides time to address any issues with the sealant barrier. Resealing before each cold season maintains the protective coating.

Even properly sealed schmear requires inspection after winter for any new cracks needing repair. But sealing minimizes freeze-thaw problems that plague untreated, porous cement finishes.

Does New or Old Schmear Need to Be Sealed?

New schmear should be sealed 10-14 days after application when cured but not aged. Sealing new schmear provides maximum protection and prevents premature damage.
Old schmear can benefit from sealing at any age, but test absorption first. Very old, powdery schmear may need re-skimcoating before sealing for best results. Clean off dirt, efflorescence, grime before sealing aged schmear.
Previously sealed schmear needs resealing every 5-10 years as sealers gradually wear off. Prepare surface, test absorption, and reseal fully for ongoing protection.

So whether newly applied or decades old, German schmear plaster can gain durability and longevity from proper sealing. Timing and preparation may vary depending on age and condition. Consult a pro for guidance sealing aged, damaged, or poorly adhering schmear.

Does Color of Schmear Affect Sealing Recommendations?

Traditional German schmear features a white-grey plaster finish. But modern versions can incorporate pigment for different colors. While white schmear is common, many opt for tan, brown, rose, yellow, or other shades to complement the brick.

The color of the schmear plaster generally does not impact sealing recommendations. The same masonry-grade sealers like silane/siloxane products appropriate for white schmear are also suitable for colored variants.

One consideration with colored schmear is that sealers tend to enhance or darken the existing shade. So the final appearance may be slightly altered, especially with lighter pastel colors.

Always test the sealer in an inconspicuous area first to ensure you are satisfied with the outcome before applying it to the entire surface. This will reveal any coloring effects or changes to the plaster texture.

For significant color change with sealing, adding universal tint to the sealer is an option to help match the original schmear tone and prevent a drastic shift in hue.

With colored schmear, extra care is needed in applying the sealer evenly and avoiding drips which may appear more obvious against the darker plaster. But sealing is still recommended for protection on any schmear shade.

What Precautions Should Be Taken When Sealing Schmear?

Carefully follow manufacturer instructions for surface prep, application, dry time, and additional coats.
Prevent overspray or drips onto other surfaces – glass, wood trim, landscaping, etc.
Ensure full coverage without gaps – seal entire schmear surface evenly.
Allow adequate drying time between coats as specified by product guidelines.
Wear protective gear when spraying sealer – gloves, goggles, mask, respirator. Work in ventilated area.
Protect newly sealed schmear from rain, sprinklers, traffic for at least 48-72 hrs while curing.
Do not apply sealer if temperatures are below 50 degrees Fahrenheit.
If using a ladder for upper surfaces, follow safety protocols against falls.
Properly dispose of all solvents, rags, and other sealant products when dry.

Conclusion

Sealing German schmear plaster provides an added layer of protection against the elements, dirt accumulation, and natural aging processes. For many projects, the inherent durability of cement-based schmear is sufficient without sealing. But in harsher climates or for improved longevity, applying a specialty masonry sealer offers insurance against cracking, freeze damage, efflorescence, and premature wear.

Silane or siloxane-based sealers formulated for concrete and masonry offer the best penetration, breathability, and performance for schmear finishes. Following manufacturer guidelines for proper application timing, technique, and drying is essential. Consulting a professional contractor is recommended if the schmear needs extensive repair or if access is difficult.

With the right sealing product and method, German schmear can maintain its aesthetically pleasing whitewashed look for decades to come. Careful sealing provides protection both when the finish is newly applied and as it naturally weathers over time. Achieving the optimal aged effect without accelerating deterioration is the goal of sealing schmear the right way.

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