Recent Projects



Client: St. Columbas Church

Location: Glen Swilly, Letterkenny

Stone Seal provide a safe and effective solution towards enhancing the aesthetics of natural stone floors. This article will focus on the levelling of granite floor surfaces in St. Columbas Church, LoughSwilly, Co. Donegal.

The Church underwent a full renovation and Millennium Cream Granite tiles were selected as the floor choice.



Following the tiles being placed, an architectural audit found that the floor was completely uneven. After the clients first attempt of restoration, Stone Seal were referred to fix the problem, improve on the aesthetic appearance and make the surface level. The main issue Stone Seal encountered was lippage, caused by a variation of the tile size modules. The tile size varied from 12 ml to 16 ml and 18 ml.

Lippage is a condition where one edge of a tile is higher than an adjacent tile, giving the finished surface an uneven appearance, in turn it causes picture framing which is the appearance of a halo around the edge of the stone. Lippage is influenced by many factors such as;

  • The allowable warpage of the tile or stone modules.
  • The spacing or separation of each tile module, which would influence a gradual or abrupt change in elevation.
  • Angle of natural or manufactured light accentuating otherwise acceptable variance in modules.
  • Highly reflective surfaces of tile or stone modules accentuating otherwise acceptable variance in the modules.



To resolve this problem for our client, Stone Seal utilized the method of diamond grinding and honing mechanical restoration.

As diamond technology developed for quarrying stone, so did this method of polishing and restoring stone. The process uses diamond abrasives, which last much longer than other conventional abrasives. The diamonds are affixed to a flexible support material with a bonding agent known as resin.

Diamond abrasives range from 30-grit to 3OOO-grit in the more popular textures. Like stones or screens, they must be used progressively in order to get a smooth, highly reflective finish.

  • To begin, Stone Seal assessed the worst the area of the floor to determine the maximum amount of lippage, the result was 4-5 ml, which resulted in three sets of metal.
  • First set of granite metals are the coarsest, and they work to remove deep lippage.
  • The next step involves eliminating the scratch pattern that resulted from the initial heavy grinding. These metals work to further reduce the scratch pattern from the first metals.
  • Following grinding, the first stage of honing by resin begins. This stage is important as it removes all scratch patterns from the metal diamond grinding stages. The process of honing is to close the pores of the stone, which results in depth and clarity when polished.
  • Crystallisers are then used to polish the stone and create what is called the beilby layer. This layer is amorphous without regular crystalline structure and is formed on the surface of metals via mechanical working, wearing, or mechanical polishing. This process ultimately achieves the glow and wow factor.
  • The last stage involves polishing with crystal blue which close the micro porosity of the stone and the gives the finished surface.

Stone Seal are based in Dublin and complete restoration work throughout Ireland. If you have a query or would like more information on our Granite restoration service, call us on 01 8770436 or fill out the ‘request an estimate’ form on this page.