Stucco is a durable and low-maintenance exterior finish for homes that has been used for centuries. Understanding the basics of stucco, proper application techniques, as well as weighing the pros and cons can help homeowners decide if a stucco house finish is right for their home.
What is Stucco?
Stucco is a type of exterior plaster finish composed of Portland cement, sand, water, and lime. It is applied wet and hardens to form a stone-like, decorative finish for exterior walls. Stucco has been used since ancient times, originally made from lime and sand. Modern stucco uses Portland cement which gives it higher strength and more weather resistance.
The stucco mix is applied in several layers directly onto the exterior wall surface. The base layer bonds the stucco to the wall and provides bulk. It is followed by the scratch coat, then the brown coat, and finally the finish coat which provides the decorative texture and color. The layers of stucco must be allowed to cure and dry properly between applications.
Benefits of a Stucco House Finish
There are many benefits that make stucco a popular and practical finish for home exteriors:
- Durability – Properly applied stucco lasts for decades. It is impact and crack resistant. Stucco’s hardness and thickness make it very durable and long-lasting.
- Low Maintenance – Stucco requires little maintenance other than occasional cleaning or repainting. It does not require staining, waterproofing, or other frequent treatments needed for wood or fiber cement siding.
- Weather Resistance – Stucco withstands all types of weather extremely well. It repels water and resists damage from rain, snow, wind, and sun exposure.
- Fire Resistance – Stucco is non-combustible and fire resistant. This provides safety and security for the home.
- Design Versatility – Stucco can be applied in many textures and patterns. Any color can be achieved with paint or colored stucco coatings. This allows great customization of the home’s style.
- Energy Efficiency – The mass and thickness of stucco offers good insulation for the walls of the home. This improves energy efficiency and reduces heating and cooling costs.
- Curb Appeal – Stucco provides an attractive, unique, stone-like appearance. Going with a stucco finish can raise a home’s curb appeal and value.
How is Stucco Applied?
Applying stucco is a multi-step process requiring some skill to get a quality finish. Here are the basic steps for applying traditional stucco over a framed exterior wall:
Install Lath
Lath are thin strips of metal, plastic or wood attached to the exterior wall studs. They provide a base that bonds and keys the stucco in place. The common types of lath include:
- Wire lath – Galvanized or stainless steel mesh. Most versatile type of lath for both flat and curved surfaces.
- Wood lath – Narrow, vertical wood strips, popular in older homes.
- Expanded metal lath – Sheet metal with diamond shaped openings. Not ideal for curved walls.
Proper fastening of the lath is critical, using galvanized nails and lath washers spaced no more than 6 inches apart. The lath strips overlap each other at least 1 inch.
Apply Scratch and Brown Coats
The stucco base layers are mixed quite stiff, with a rough texture, and trowel applied:
- Scratch coat – The first layer that bonds the stucco to the lath and wall. It fills gaps and provides the base thickness. Applied 3/8 to 1/2 inches thick.
- Brown coat – Second layer, also called the float or leveling coat. Builds thickness and provides a smooth, even surface for the final coat. 3/8 to 1/2 inches thick.
These coats must dry and cure completely, typically taking 7-14 days, before the finish coat can be applied.
Finish Coat and Texture
The final decorative layer of softer stucco is applied 1/8 to 3/8 inches thick. Numerous textures can be achieved by the technique of troweling or brushing the finish coat:
- Smooth trowel – A flat polished stucco surface, the most common and easiest finish.
- Sponge float – A slightly rough sandy texture from finishing with a damp sponge.
- Broom finish – Pulling a broom across the surface gives a lined texture.
- Splatter texture – Thrown or splashed on with a whiskbroom for a speckled effect.
- Lace finish – Patterned ridges created by trowel marks.
Curing and Caulking
Curing allows the stucco time to fully hydrate, dry, and harden before it is painted. Wait at least 2-3 weeks after the finish coat dries before painting. All joints and gaps must then be caulked. Use a premium, paintable exterior caulk matching the wall color.
Paint Finished Stucco
Quality acrylic or elastomeric paint provides the final color coat, protection from weathering, and increased durability for the stucco. Two coats of primer and paint specifically formulated for cementitious surfaces such as stucco is recommended.
Pros of a Stucco Exterior
There are many advantages that make stucco a smart choice for a home’s exterior:
Extreme Durability
The foremost advantage of stucco is its incredibly durable, solid structure. Stucco walls can last 50-100 years when properly maintained. The material itself is non-combustible and impact resistant. It holds up to decades of weather without rotting, decaying or needing replacement.
Once installed, stucco requires almost no upkeep beyond occasional cleaning and paint touch up every 10-15 years. It does not warp, split, or crack like wood siding can. The cement-based material is highly water resistant.
Thick stucco requires no sealing or caulking against the elements. Minor hairline cracking may occur with shifting foundations but does not affect the performance. The longevity of stucco boosts the home value.
Low Maintenance Exterior
Since stucco lacks joints or seams, and is non-porous, it does not provide space for mold or pests to enter. There is no need to periodically re-caulk gaps or replace damaged pieces as required with other sidings.
Stucco only needs occasional low pressure washing to remove dirt and re-painting every decade or so. This saves homeowners countless hours of maintenance over the life of the home.
Design Flexibility
Stucco offers almost unlimited possibilities for textures and patterns applied during finishing. It can be troweled smooth, brushed, swirled, splattered, textured with lace patterns, and more. This allows creative customization of the home.
In addition, stucco can be tinted or colored during application, or any shade applied with paint. The color options are limitless. Contrasting base and trim colors can be boldly used with the texture and patterns. This flexibility in design allows stucco homes to stand out.
Energy Efficiency
Stucco insulates well due to its thickness and monolithic coverage of the exterior walls. This provides an effective weather barrier that helps moderate indoor temperatures. Homes with stucco walls have lower heating and cooling costs compared to other sidings.
The thermal mass and air tightness also provide sound dampening. Stucco homes are extremely quiet inside. The energy savings and comfort are substantial benefits.
Fire Safety
As a non-combustible cement product, stucco is completely fireproof and safe. This is invaluable protection for homes located in wildfire prone regions. Stucco will not burn, adding critical resistance against an advancing wildfire, allowing residents to evacuate.
Curb Appeal
The sculpted, stone-like look of stucco exteriors provides unique visual interest and beauty. The variety of available textures and patterns, along with any color, enables great curb appeal. For home buyers, stucco evokes Old World charm, sophistication, and quality construction.
Cons of a Stucco Exterior
While having many advantages, there are also downsides and disadvantages to consider with a stucco exterior:
High Initial Cost
Professional installation of stucco is significantly more expensive than other siding options like vinyl, wood, or fiber cement. Multiple labor-intensive steps are required along with specialized tools and materials. This high upfront investment may deter some homeowners.
However, cost-benefit analysis over the entire life of the home favors stucco due to its extreme durability and lack of maintenance or replacement costs.
Skilled Application is Critical
A poorly applied stucco job will fail prematurely. The multiple layers must be mixed, proportioned, applied, and cured correctly. Many factors like weather, sun exposure, and moisture management impact the process.
An unskilled or inexperienced contractor often leads to major cracking, instability, and other defects that undermine stucco’s benefits. Hiring a reputable, specialist stucco contractor is advised.
Not a Do-It-Yourself Project
Applying stucco is simply not a DIY project for most homeowners. All the specialized tools, materials, mixing knowledge and application techniques make professional installation a necessity. This means the cost savings of owner-done work is not an option.
Added Wall Thickness
Since stucco consists of multiple layers that add 1 to 1.5 inches in wall thickness, it reduces the interior space of rooms very slightly. For large expansive homes this is usually not an issue, but must be considered with smaller floorplans.
Difficult Repairs
While stucco lasts for decades, when cracks or damage does occur, repairs require cutting out the affected area, then re-stuccoing and matching the texture. This makes stucco repairs more difficult and costly than simple vinyl siding replacement. Matching the existing stucco finish can be tricky.
Not for Cold Climates
In areas with extended freezing weather, stucco has an increased chance of frost damage or cracking, especially if there is a lot of water in the mix. So it is not the optimal choice for the harshest northern climates that get heavy snow and ice.
FAQs About Stucco Home Finishes
Does stucco add value to a home?
Yes, stucco can increase a home’s value, especially in regions where it is less common. The customized appearance, perceived quality construction, durability, and low maintenance are attractive features to home buyers. The value boost can range from 3-5%.
How long does stucco last?
With proper installation and maintenance, a stucco exterior will last from 50-100 years, thanks to its cement-based composition. This extreme durability and longevity is why stucco maintains popularity as an exterior building material.
Is stucco expensive to repair?
Yes, stucco repairs tend to be costly. The affected area has to be cut out and re-stuccoed with multiple new layers that are matched in texture and color. The labor and specialized skills required drives up the repair costs compared to other sidings.
What kind of paint is used on stucco?
An acrylic or elastomeric masonry paint specifically formulated for stucco and concrete surfaces is ideal. It allows flexibility to prevent cracking or peeling as the stucco expands and contracts. Two coats of primer and paint ensures proper coverage and durability.
Is stucco waterproof?
While very water resistant, stucco is technically not 100% waterproof. It is porous enough that water can penetrate, especially if cracks are present or if moisture gets behind the stucco. A water-resistant barrier on the exterior walls is recommended.
How often should stucco be painted?
Stucco paint holds up well but will fade and weather over time. Every 10-15 years the stucco should be repainted, ideally using an elastomeric paint that can flex with the stucco’s expansion and contraction.
Can stucco be installed over brick?
Yes, stucco can be applied over existing brick, concrete, cinder blocks, or other masonry surfaces. Lath is secured to the wall, then the scratch coat is applied directly onto the brick. This is an option for changing the look of a brick exterior.
Is stucco OK for humid climates?
Humidity is generally not a problem for stucco walls as long as drying time between coats is extended to ensure proper curing. However, tropical or coastal climates with salt air or consistent heavy rain may shorten the life span of stucco due to increased weathering.
What wall surface is best for stucco?
Concrete, concrete masonry blocks, and brick all provide excellent substrates for stucco. Wood or metal framed walls sheathed with a water barrier and lath also works well. The surface must be clean, smooth and properly prepared to bond with the stucco base layers.
Conclusion
Stucco has been used for centuries across the world as an attractive yet extremely durable exterior wall finish. When properly installed by a skilled contractor, a stucco home finish offers many benefits like longevity, weather-resistance, design flexibility, and fire safety. It adds value and curb appeal to homes with its customizable textures and colors.
The main downsides are the high initial cost and the difficulty of repairs. Stucco requires expert application, so a quality outcome relies heavily on hiring the right contractor. Homeowners who don’t mind paying more upfront for the virtual elimination of exterior maintenance expenses in the coming decades may find stucco the ideal choice for their next home. With its pros and cons carefully weighed, stucco remains a high-performing and cost-effective option for exterior finishes.