Reference and installation guide to help you select the proper substrate

At Basco, we understand the shower is the centerpiece of your dream bathroom masterpiece. It is what has inspired us to craft the finest custom shower enclosures for decades, providing the ultimate finishing touch for your retreat.

Selecting the proper substrate for your shower door is as important as selecting the enclosure itself, so it is with this in mind that we encourage our customers to understand the differences between acrylic and gel-coat/fiberglass and to consider which doors are appropriate for each application.

How Materials Impact Shower Door Options

Choosing the perfect material for your tub or shower is important when designing your dream bathroom. Today’s acrylic and gel-coat fiberglass modules provide a variety of options to achieve the look you want and to enhance your bathing experience. Let’s consider the differences and how your shower door choice is affected:



  • Acrylic is an extremely durable bath and shower material. With its strong acrylic surface and composite backing material, it’s resistant to the rigors of everyday life — no cracks, no chips.
  • Depending on use, acrylic may require less maintenance than other bath materials. Its non-porous surface makes cleaning with a non-abrasive cleanser simple and easy.
  • Many modern acrylic modulars have structural ribs behind the base for additional support.
  • Acrylic retains its color, luster and showroom condition longer. Because its color goes through the thickness of the material, it’s resistant to dulling and fading.
  • Acrylic warms and cools faster than other tub materials, so in a warm room, an acrylic tub is warm to the touch. During a bath, an acrylic tub will keep water warmer for a longer amount of time.
  • Acrylic modules that install straight to studs using screws are appropriate substrates for any 3/16” or 1/4” glass shower enclosure.
  • Acrylic shower walls that install by gluing panels to drywall are NOT an appropriate substrate on which to install any shower door.
Acrylic Sample Images


  • Gelcoat is short for “gel-coat fiberglass reinforced polyester,” more popularly known as “fiberglass.” The “gel-coating” is a thin layer of smooth, shiny material that lays on top of the fiberglass. It is what gives the material its smooth finish and its color. The fiberglass reinforced polyester lies beneath, and it is what gives the material its strength.
  • Gelcoat bathing material is lightweight and easy to maneuver. For its weight, it is extremely strong, flexible and durable.
  • With proper cleaning and upkeep, gelcoat tubs will keep their color and luster for a long time. Because gelcoat surfaces are slightly more porous than Acrylic surfaces, they can stain over time if not properly cleaned and maintained.
  • Gelcoat fiberglass modules that install straight to studs using screws are appropriate substrates for any 3/16” or 1/4” glass shower enclosure.
Fiberglass Sample Images

Check our cross reference to find your model and the doors that fit.

Installation Guidelines

Heavy Glass Installation Guidelines for Fiberglass & Acrylic Fixtures

Our intent at Basco is to ensure that our customers have access to the products they desire based on their style and preferences. As such, please refer to these guidelines for installing heavy glass doors on fiberglass and acrylic substrates.

Structural Support Guidelines for Fiberglass & Acrylic Fixtures:

  • A RODA door on acrylic or fiberglass requires proper backing to ensure stability.
  • A single 2 X 4 stud is needed behind the wall where the header meets the wall on top and bottom pivot units.
  • A double 2 X 4 stud is needed behind the wall on the hinge side for wall mount hinges.
  • A double 2 X 4 stud is needed at the threshold for hinge mounting and support of the weight.

Precautionary Guidelines:

  • When the U-Channel or glass clamp is screwed into the threshold, the weight of the glass sits on top of the screws, necessitating the structural support.
  • Without proper structural support, when the panel or door is moved this could cause the screws to move slightly. Over time, this slight movement enlarges the hole the screw is in and eventually cracks (spider webs) the gelcoat or acrylic and begins to break down the fiberglass backing.
  • Acrylic or fiberglass walls have blocking installed by the manufacturer. However, the location of that backing may not match the location of where holes need to be drilled for vertical u-channel, wall mount hinges, and headers.
  • Without proper backing behind the walls the door or panel(s) will eventually slip out of the thin walls.
  • All structural elements of RODA doors must follow these guidelines. These elements include but are not limited to: hinges, headers, and clamps.
  • Basco requires a minimum of 1-1/4” thread engagement of all fasteners into the blocking at any load bearing location. Depending on the application the customer may be required to supply the proper fasteners to ensure adequate engagement.
  • U-Channel may be secured into areas without blocking, excluding fiberglass and acrylic modules and/or bases, when wall plugs are used. Fiberglass and/or acrylic modules require proper blocking in all locations, including a u-channel.
  • Metal studs or strapping are not acceptable substitutes for securing load-bearing hardware.
  • Always refer to local building code. Local building code may supersede Basco’s requirements. Basco’s requirements are to be regarded as minimum requirements.

Structural Support Visuals

Two 2x4 studs - Floor-to-Ceiling, 90 degrees to other studs secured together.

Blocking Option 2

Aerial view of mounting point support

Blocking Option 2 2

Bathroom perspective with structural reference

Horizontal blocking between vertical studs - Attach lumber at required locations horizontally between other floor-to-ceiling studs.

Blocking Option 4

Aerial view of mounting point support

Blocking Option 4 2

Bathroom perspective with structural reference

Heavy Glass Models

Heavy Glass Models for Fiberglass and Acrylic

The following heavy glass (3/8" glass) models have been specifically designed or approved for installation on fiberglass and acrylic modulars. For the Coppia and Fusion doors, additional structural support is not required, but is still highly recommended.

Rotolo Semi-Frameless Bypass Rolling Doors

  • Bypass panels - both panels slide in the enclosure
  • Sleek, modern header with visible top rollers
  • 3/8” heavy glass
  • Single exterior towel bar and one back-to-back knob
  • Easy, reversible installation for left or right entry
  • Required threshold width is 2-3/4”
  • Standard model - RTLA-905
  • Custom model - RTLH-905

Coppia Adjustable Single Swing or Swing Door & Panel

  • Up to 1” adjustment on the single swing (1/2” on hinge side, 1/2” on handle side)
  • Up to 1-1/2” adjustment on the door and panel (1” on the panel side, 1/2” on the hinge side)
  • 3/8” heavy glass
  • 8” through-the-glass handle
  • Door swings out only
  • Easy, reversible installation for left or right entry
  • Single swing model - COPA-900
  • Door & panel model - COPA-935

Fusion 1/4” Glass Swing Door & 3/8” Glass Panel

Celesta Semi-Frameless Bypass Sliding Doors

Cast Iron & Steel

Additional Substrates - Cast Iron & Steel

We recommend any of our bypass sliding units, including the Celesta 2850 tub or 3850 shower, or Rotolo RTLA-905/RTLH-905, as well as any Basco framed or semi-frameless swing door for installation on cast iron or steel.

While cast iron or steel tubs or shower pans maybe able to support the weight of a RODA door, it is not possible to drill into these materials. Properly installed RODA doors require mechanical fastening to the floor material.

Glass Tile

Glass Tile

Glass tile is beautiful and gaining popularity, but it also makes the installation of a shower door challenging because glass tile is delicate and can break easily during an installation. Typically, the damage occurs when the screws are being tightened down, not during the drilling of the mounting holes as one might expect. Even if the tile does not break right away, it will likely happen shortly after the installation because the weight of heavy glass doors is too much on delicate glass tiles. While there is no way to prevent potential damage to existing glass tiles, we do have a suggestion for those who are set on glass tiling:

If it is a bathroom remodel and you plan to install glass tile, we recommend that you plan a strip of more durable porcelain or ceramic tile along the wall and curb where the shower door will be installed. A matching color or an accent color tile can look lovely and blend beautifully into the shower door setting. This allows a damage-free installation while ensuring a secure fit.

While glass tile is less problematic with thinner, framed shower doors, such as our Deluxe Series, we still recommend taking precautions and installing a non-glass-tile trim.

Looking for a Door to Fit Your Acrylic or Fiberglass Fixture?

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