Silicone: yes you can
Dispelling myths and clarifying facts about silicone's role in period and listed buildings. We explore when and how to use it effectively, guiding homeowners, tradespeople, and specifiers through the nuances of this versatile material.
Yes, you can use silicone! - but only the right one
Contrary to popular belief, and the usual nonsense from armchair experts, silicone can be a valuable material in the restoration and conservation of period and listed buildings. We understand the importance of appropriate material selection. The key lies in understanding the right type of silicone for the right application, ensuring both durability and respect for historical integrity. This page is designed to help homeowners, trades, and specifiers make informed decisions, ensuring your projects benefit from modern solutions without compromising heritage values.
High or low modulus silicone?
Understanding the difference between high modulus and low modulus silicone is crucial for success in restration projects. High modulus silicones offer greater rigidity and are suitable for more modern applications requiring minimal movement, such as sealing rigid joints.
Low modulus silicones, on the other hand, provide greater flexibility and are ideal for joints subject to movement, like those found in older buildings that naturally expand and contract. Choosing the correct type ensures longevity and prevents damage, maintaining the building's fabric.
Low Modulous Silicones are moisture Vapour Permeable, whilst maintaining there adhesive quantities and can be over painted when dry.
LMS sealants expand by 10% in size without losing adhesion, meaning they will expand and contract along with building elements. LMS sealants are used to seal expansion joints in brickwork, so they are also weatherproof.
So HMS or LMS?
When approaching conservation and restoration work, the choice between High Modulus Silicone (HMS) and Low Modulus Silicone (LMS) can significantly impact the outcome. HMS is often preferred for its strength and adhesion, suitable for glass or non-porous surfaces. LMS, with its superior flexibility, is better for porous materials like brick, stone, or timber, accommodating natural movement and preventing stress cracks. Heritage Lane advises careful consideration to match the silicone's properties with the specific needs of your building's materials and structural dynamcs.
But not Acetoxy
Acetoxy is a more modern silicone sealant, often called "acid sealing" because it contains an acid which speeds up the drying process, however during this drying process a 'vinegar' aroma is given off so the first part of the name could easily stand for "acetic", but Acetic is an organic acid, so it's safe and simpler to just remember "acid sealer" this "acid" also acts as a mould inhibitor, and with this particular sealant drying to a hard, impermeable finish, it's one to be conscious of with regards to traditional buildings. And to finish off, the last part of 'oxy" refers to the oxidisation (air drying) of the surface to protect the chemistry going on beneath the surface, similarly to how Linseed Oil Paints dry.