Last Updated: 7 April 2026
Whether you are considering an order or have already received your SIMBA S312DTL7 adhesive shower seal, you may be wondering how to achieve a seamless finish where it meets your vertical strips (such as magnetic or H-profiles).
The corner join is frequently the most vulnerable point for leaks. While the bottom seal features an inward-sloping Drip Rail, vertical seals typically sit flush against the glass edge. If the transition is not managed correctly, water can easily seep through the junction.
The Professional Secret:
- Notching: By cutting a precise notch into the rigid base of the adhesive seal, you allow it to neatly contour around the vertical strip.
- Verticals First: Always install your vertical seals first. This allows you to measure and cut the bottom seal to the exact remaining width.
Follow our practical steps below to create a professional-grade watertight barrier:
1. Tools for a Precise Finish
To ensure clean edges and a lasting bond, we suggest the following:
- Heavy-duty Snips or Garden Pruners: The S312DTL7 base is robust. Standard office scissors or craft knives may struggle.
- Fine-tip Marker: For millimetre-perfect alignment marks.
- Alcohol Wipes & Lint-free Cloth: Essential for removing "invisible" oils and soap residue.
2. The Logic of the Join: Alignment and Precision
The S312DTL7 is designed to be fixed to the internal base of the glass, creating a snug butt-joint with your side magnetic or H-profile strips.
Step-by-Step Installation:
Surface Preparation: Clean the glass thoroughly with alcohol. Avoid cleaners containing silicone or oils, as these can hinder the adhesive’s long-term bond.
Fit Vertical Seals First: Secure your vertical magnetic or side seals first. If these are discoloured or brittle, consider replacing them alongside your bottom seal.
Browse: Vertical Shower Seal CollectionsPosition & Mark: Hold the S312DTL7 against the glass, overlapping the vertical seal. Use your marker to indicate the width of the vertical strip on the base of the new seal.
Define Notch Depth: Move the seal behind the vertical strip to mark how deep the "notch" needs to be to clear the vertical profile.
Precision Notching: Using your snips, carefully remove the excess rigid base material according to your marks. Expert Tip: Follow the "measure twice, cut once" rule. Leave a 2mm margin for a trial fit.
Fixing in Place: Peel the 3M backing and press the seal firmly against the glass. Ensure the sloping drip rail faces inward toward the shower tray.
3. Professional Bonding Techniques
- Thorough Degreasing: Always use a dedicated agent like alcohol.
- Dry Run: Simulate the fit first. Repeatedly removing the seal will weaken the adhesive.
- Activate the Bond: Once positioned, apply firm pressure with your thumb for at least 20 seconds. This pressure "wakes up" the bond.
4. The Final Check: The Tissue Test
Allow the adhesive to cure for 8–10 hours before use. Place a dry paper towel outside the corner join and direct the showerhead at it for one minute. If it remains dry, you have a professional seal.
Purchase: SIMBA S312DTL7 Adhesive Shower SealIf you require a different style, visit our Shower Door Bottom Seals Category. For standard U-channel guide, see Bottom or Vertical Seal: Which to Install First?.
FAQ: Installation Details
Will the adhesive hold in a wet environment?
What if I over-trim the seal?
Is this suitable for my glass thickness?
What if my glass has a curve or metal trim?
Which way should the Drip Rail face?
If my vertical seal is very thick, will it sit flush?
Will the adhesive damage my glass?
Will mould grow behind the adhesive tape?
What if the adhesive discolours over time?
Professional Support: If you encounter a unique angle or a challenging frame, please send a photo to our support team. We aim to provide a personalised fitting suggestion within 24 hours.