Applying cement over a fiberglass shower is possible but requires careful preparation. The non-porous fiberglass surface must be sanded to help the cement adhere. A high-quality bonding agent is also necessary.
Correct cement mixing, application, and curing are essential for a lasting finish. Although this can be more affordable than replacing the shower, professional advice is recommended to avoid issues.
Understanding Fiberglass Showers
Fiberglass showers, made from fiberglass-reinforced plastic, are common due to their easy installation and minimal upkeep. These units are lightweight, durable, and have a smooth, non-porous surface that resists moisture and inhibits mold and mildew growth. However, the surface may wear over time, showing scratches and stains, leading homeowners to consider resurfacing options like concrete application to improve the shower's look.
Applying concrete to a fiberglass shower requires careful preparation to ensure it sticks and to prevent water damage. The different properties of flexible fiberglass and rigid concrete must be considered to avoid cracks in the overlay. Special attention is needed to waterproof the areas where the shower base meets the walls to prevent leaks.
The Cementing Process
The cementing process includes several steps to successfully apply a concrete overlay onto a fiberglass shower unit. First, the fiberglass surface must be cleaned and sanded to create a rough texture for the concrete to adhere properly. Any damage should be repaired to avoid issues with the new surface.
Next, a layer of mortar or concrete is applied to the shower pan and walls to create a strong foundation that supports the overlay and reduces the risk of cracking. This base must be level and even.
After the base layer sets, the concrete overlay is applied evenly across the shower pan and walls with appropriate tools to ensure smoothness and consistent thickness.
For a decorative finish, designs can be stenciled or carved into the concrete walls. The surface is then sealed with a waterproofing sealer to prevent moisture absorption. Optional concrete vanity tops and tub surrounds can be added for a cohesive look.
Necessary Tools and Materials
To cement over a fiberglass shower, you need specific tools and materials:
- A cement board suitable for wet areas
- A steel mud pan
- A putty knife
- Mesh tape
- A waterproofing agent like Redguard
The cement board provides a solid base for the cement. Use the steel mud pan to mix and hold thin-set mortar. A putty knife will assist in spreading the cement evenly.
Mesh tape reinforces seams between cement board panels to avoid cracks. Apply it to the seams before adding cement, embedding it into the thin-set for stability. The waterproofing agent is critical to prevent water from reaching the fiberglass shower, preventing structural damage.
Prepare all tools and materials beforehand for an efficient application and a quality finish. The right products and tools are essential for a successful job.
Preparing the Shower Surface
After gathering the necessary tools and materials, the next step is to prepare the shower surface for cement application, which is crucial for cement overlay longevity and durability.
First, clean the shower walls to remove soap scum, oils, or mold. Sand down any loose fiberglass to roughen the surface for better mortar adhesion.
Then, install moisture control by laying felt paper on the shower base as a protective layer, and staple wire lath over it to the plywood. The lath must be flat and tight against the walls to provide a stable base for the mortar and prevent future movement.
Mix the mortar to a stiff consistency and form an 18-inch diameter circle on the base, adjusting for the base size and following manufacturer's guidelines.
Applying the Cement Layer
After preparing the shower surface, the next step is to apply the cement layer. This is important for creating a stable and even base. The layer needs to be applied carefully to avoid future problems like cracks or water damage.
Professionals use a trowel to evenly spread a concrete overlay mixture on the fiberglass. The mixture should stick to the surface and provide a strong base once it dries. It's important to keep the layer thickness consistent to prevent any weak spots.
The cement layer also allows for decoration, such as adding mosaics or creating patterns that look like tiles. These designs enhance the shower's appearance.
For showers designed to be like a spa, the cement layer can be made from precast polished concrete panels or troweled concrete on a wooden subfloor. This can create a continuous look without needing a shower curb, giving a minimalist and calm feel.
Applying the cement layer combines technical skill and attention to detail. It is essential for a successful installation that is both functional and custom-designed.
Drying and Curing Time
It is essential to allow adequate drying and curing time after applying a cement layer over a fiberglass shower to ensure structural stability and proper appearance. The cement overlay's long-term performance depends on proper setting and bonding with the surface beneath it. Short drying times can result in a weak foundation prone to cracking, crumbling, or poor adhesion, potentially leading to expensive repairs.
The time required for drying and curing varies, influenced by the ambient temperature, humidity, ventilation, and the specific products utilized. For example, Ardex products typically need a minimum of 24 hours of drying before additional layers or sealants are applied. This period is crucial for the mortar to achieve the necessary hardness and a solid bond with the fiberglass.
When using other materials, such as Henry Feather Finish Patch and Skim Coat, manufacturers' instructions should be consulted for accurate drying times. These products may have unique characteristics and drying time requirements to reach the desired strength and finish.
Patience is important to ensure the cement overlay dries and cures correctly. Skipping or rushing this step can compromise the shower remodel's integrity, leading to poor results or the need for further repairs. Adhering to the recommended time frames is advised to achieve a durable and well-finished result.
Potential Complications
Applying cement over a fiberglass shower can provide a new look and improve stability. However, it's important to manage moisture to prevent mold. A vapor barrier is necessary to protect against moisture issues.
Adding a concrete layer may affect how shower door channels are secured. The cement's thickness requires evaluating the anchoring system to ensure the doors remain stable and secure.
The shower floor's slope and drainage need careful planning. Incorrect slopes can cause water to pool, increasing the likelihood of mold and risking structural damage due to cracking. Regular maintenance, particularly in grouted areas, is essential to prevent mold.
Alternative Renovation Options
Homeowners can choose from several options when upgrading their showers, such as installing acrylic liners or replacing the entire fiberglass unit. These methods offer a refreshed look without the need for a concrete overlay.
Acrylic liners are tailor-made to fit over existing showers, covering old designs quickly. This option is convenient for those wanting a quick and clean update, as it doesn't involve demolition. Acrylic also resists mold and mildew, maintaining a cleaner bathroom.
For a complete renovation, replacing the fiberglass unit is an option. It allows for customization in design and size, and the chance to update plumbing and fix any damage or mold.
Wall surrounds are another choice, available in materials like solid surface composites or PVC panels. They mimic the look of stone or tile without requiring grout or heavy maintenance.
