The Importance Of Fixings In Masonry Construction
This week, we are talking about fixings in masonry.
We know (or hope!) all the stonemasons out there will know the following information, but we are also very aware that our customers don’t.
We write these blogs in an effort to explain the craft of stonemasonry, in more depth (without as much of the technical jargon as we can), and to help our customers understand, and indeed question, the processes we use.
We are always on hand to answer any queries, and there are no stupid questions (trust me, as the non-stonemason in the company, I ask a LOT of questions). Not only are fixings essential on stonemasonry, it is imperative that they are used correctly.
But what are they?
In layman’s terms (ie my definition!), fixings are metal components, used within masonry to help secure stone in place, just like here…
However, this is really where my knowledge of fixings ends, so I turned to Scott, our managing director, for some information, this is what he said……..
“At Stratum Masonry we have a very experienced team of stonemasons.”
Over the years we have witnessed numerous types of materials used, both correctly and incorrectly, in stonemasonry. When it comes to fixings, we’ve seen copper, phosphor bronze, cast iron metal, galvanised metal, and stainless steel, to name a few.
All of these materials have been discovered by our team, on various restoration projects over the years. While they each have a place of their own within stonemasonry, only stainless steel should be used to prevent corrosion or defects to the stone unit itself.
Before stainless steel was the recognized material, copper and phosphor bronze were the go-to material for the older generation of stonemasons. They served a purpose, and to this day…
“they are still holding out on masonry items that were fixed back then.”
Today it’s stainless steel fixings which are specified and used (or at least should be!). We have a good working relationship with a few, select, companies who supply ourselves at Stratum Masonry with high quality grade stainless steel (EN 1.4301 304) Below is a photo of a stainless steel ‘dog cramp’ which is used to hold 2 x masonry items together. This would, for example, be used on a stone balustrade.
In recent years there have been a few high-profile cases where fixings have been used inappropriately and not often within specification guidelines. Failure to comply with these specifications can cause serious issues further down the line. Take, for example, this article concerning new build schools;
The problems highlighted were caused by a lack of fixings within the façade structure. When Stratum are working on projects where stone replacement or rebuilding works are taking place, we always take the approach from a public and practical perspective. Take, for instance, our current project in Helensburgh. Working closely with the design team, we are rebuilding a new stone balcony which, previously, had no steel support. All parties involved are working together to provide a solution which ensures the new masonry will be installed to accommodate the new, essential, steel sections, and more importantly, the new stone is supported by the steel and supporting loads.
When installing fixings, there are many different methods and materials to be considered. In an effort to introduce you to some of these, we are going to take you through a recent case study where we installed skew copes and club skews. The materials used for this were 18mm & 10mm stainless steel threaded rod, used with a two-part epoxy injection resin (stick with us, there are pictures!)
The picture above illustrates the ‘closer’ which is the stone used to close the gap between each cope. As you can see, there are 2 x number dowels which are sticking out of the stone which are used to hold the masonry together, preventing any movement in the future. The other two holes you can see, have been pre drilled and 2 x slip dowels will be used here to make sure both ends of the masonry unit is secure.
When the stone is ready for building all 8 x pre drilled holes (4 x in masonry that has been built and 4 x in new masonry unit) will be filled with a two part epoxy injection resin which again ensures the masonry will be secure and last years to come.
Given the location of these cope stones is approx 10m high, you can appreciate how imperative using the correct fixings is!On some sites, it is fairly easy for our stonemasons to identify where incorrect fixings have been used. This is because the masonry has ‘cracks’ on its surface, and in most cases, it can be a mild steel that has been used (like cast iron, which was popular in the 1980/90’s). In these instances, the steel is fine when first installed, however, over time, when moisture passes in and out of masonry, the steel will start to corrode, causing the masonry to crack and expand. When this happens, more often than not, the masonry will need to be replaced.
The importance of highlighting the necessity for fixings in masonry is now more significant than ever!
Given the numerous stories recently covered by the media concerning fallen masonry, we think the importance of highlighting the necessity for fixings in masonry is now more significant than ever!