Shower Door Too Small For Opening – What To Do?  

Home renovations tend to create problems and complications arising from mismatched fixtures, errors in measurements, and incompatible structures. There are several ways to resolve a too-small shower door. We have researched how to provide cost-effective solutions for your shower opening.

If the door or opening's frame is incompatible with the shower door - resulting in unwanted gaps - then the different ways to remedy the problem are by installing strips of vinyl trim, caulking, or applying shower door seals.

The size of the gap requires you to apply or use different solutions. Read on to find out more about the various cost-effective ways to address the issue.

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Vinyl Trim

Vinyl trim, also known as PVC (polyvinyl chloride) trim, is a modernized plastic material used for waterproofing and sealing large gaps between shower frames and doors. The structure is durable and hardwearing. 

Because moisture can easily penetrate wood, making it more prone to damage, vinyl trim pieces are the best materials to use instead of ordinary or wooden moldings.

How To Install Vinyl Trim

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  1. The first thing you have to do is to acquire the correct measurements of your shower door frame - you can use a measuring tape. Once finished, cut the vinyl trim into the correct sizes or dimensions with a miter saw.
  2. For an accurate and smooth finish and edges, sand the ends of the trim pieces using a sanding block.
  3. Attach the material onto the frame by applying silicone glue along the corners of the panel board then use a 1 1/4 pinch of nails or screws to affix the vinyl in place.
  4. Smear white waterproof caulk or silicone on the nail holes. Smooth out the surface with a wet fingertip.
  5. Afterward, apply the same material around the edges of the vinyl trim. Let it dry for at least 24 hours before using your shower. 


Caulk is a waterproof sealant that is used for sealing cracks and gaps. It is ideal to apply onto spaces no more than a quarter inch wide.

It generally prevents water and moisture damage around your home, especially when used around ceiling fixtures, pipers, drains, faucets, shower frames, and other materials. 

Most caulking substances are contained in disposable cartridges that usually fit in half-barrel caulking guns. Windows and door frames typically require half-cartridges while four canisters are needed for sealing the foundation structures of your home.

Pressurized containers do not need a caulking gun for application. 

There are several compounds from which the material is made, each has its own functions, adhesive qualities, and clean-up requirements. 

How to Apply Caulk

Although the process is relatively simple, proper application is still necessary to avoid any complications and to ensure proper adhesion. Use a 100% silicone caulk for best results.

Check out Gorilla Silicone Caulk on Amazon.

  1. Assuming there is old caulk or chipping paint on your shower door frame, remove debris first using a putty knife, brush, or a special liquid.
  2. Wipe and clean the frame and the surrounding areas before sealing.
  3. Ensure that the place is completely dry to avoid sealing in moisture that can affect its adhesive properties.
  4. Now, apply the silicone caulk onto the gap by slowly moving the material horizontally or vertically, depending on the direction of the space.
  5. Afterward, dip your finger into a mixture of one cup of water and dish soap then slowly glide your finger on the caulk in order to let the material dry off.  

Repeat the process on the opposite side and all the other areas that need to be caulked then wait at least 24 hours for the silicone to be completely dry before using the shower. 

Shower Door Seals

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Shower door seals effectively enclose the gaps between the door and the walls or floors of your bathroom. They prevent water puddles from forming on the surface.

Similar to vinyl trim, the material is made from PVC or plastic, making it waterproof and long-lasting. However, the product usually seals smaller spaces.

The materials are classified into two categories: lip or bumper seal and drip seal.

  • The lip or bumper seal is placed on the vertical side and efficiently seals against the wall and other glass panels.
  • The drip seal is installed at the bottom of the shower door which adequately encloses the space between the floor and door.

Seal strips are mostly sold in various lengths that can be cut to the specifications that you need. If your shower panels belong to the standard "off the shelf" dimensions, then you can acquire a full replacement kit that is already relative to the size that you require. 

How Do You Install A Shower Seal?

1. Clean And Measure

The first step you have to do is to clean the area. Remove any dirt, debris, or mold forming on the surface. Afterward, measure the length of your glass panel. Cut a strip of shower seal slightly longer to provide an allowance or extra leeway. 

2. Attach at the Hinges

Installing a shower seal on the jointed portions is relatively simple. Place the seal alongside the vertical " data-type="URL" data-id="">hinged section of the door then trace or mark the central openings of the hinges. Be sure that you have defined or outlined the exact placement of the junctures. 

Cut off the portions that would overlap them so that it would produce a perfect fit once the sealant or paneling is installed.

Attach the material by either peeling off the adhesive covering or by applying silicone glue on the surface.

3. Attach at Corners and Door Lengths

The method on how to affix the shower seal depends on the kind of material you are using. Check out this demonstration for a good visual on how it might work for your door:

To illustrate, snap-on seals have clasps or grooves that fasten or attach to the notch. It is usually used as a drip seal. Simply glide the material at the bottom edge of the door. 

Check out Shower Door Bottom Seal on Amazon.

Self-adhesives have one side that should be peeled off and adhered to the surface. It is usually installed as a lip seal.

Check out Zengest Shower Door Seal Strip on Amazon.

Basic or standard shower seals do not have any adhesion properties incorporated within them. You will need to apply a silicon glue on the material itself in order for the product to properly stick or adhere. 

Once the seal is in place, use a craft knife or a cutter to trim the excess parts. 

How Wide Does A Shower Door Opening Need To Be?

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Any shower door openings should have a minimum width of 22 inches. Any size narrower than that could violate building or safety codes. 

While this is the case, the dimensions will depend on the type of shower door. A pivot or swinging unit should have a walk-in door opening that is 26 1/2 inches wide while sliding doors require to have a width of 22-25 inches. 

When measuring the opening, it is important to get the dimensions of the top and bottom parts because walls and alcoves might have been slightly out of form or lost their shape over time. If this is the case, use the largest measurement as your basis.

How High Should Shower Doors Be?

Shower doors have a standard height of 80 inches. There should be a gap between the topmost portion of the shower door and the bathroom ceiling in order for moisture to escape. This will prevent damage or warping of your bathroom ceiling material especially if it is made of wood. 

In Closing

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Various materials can be used to properly seal or enclose unwanted spaces on your shower door. We hope this article has been insightful in providing you with ways how to resolve the issue. 

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