The term “Flagstone” actually refers to the cut of the stone, not the type of stone. Flagstone is almost always a Sandstone. Flagstone refers to the cuts and the installation with large irregular shaped pieces of stone and large grout lines. Any stones can be cut and installed as a Flagstone pattern.
Sandstone is a sedimentary stone that is deposited as mountains are turned into sand grains by erosion. After time, the sand grains are compacted together and bonded together by minerals to form a solid rock.
Interior flagstone is usually sealed with a coating. This will give it shine and protection from water penetration and stains. Coatings are not bulletproof and once a coating is applied it needs to be maintained regularly. If the coating breaks down and starts to peel off, it is llikely that a new coating will be very patchy and uneven.
Stripping is a common treatment for Flagstone that has begun to deteriorate. Stripping flagstone can be very expensive and often, not all of the old coating is removed. If the Flagstone coating is maintained before deterioration is obvious, the stone can be restored and might never need to be stripped. We use only top quality commercial grade topcoat sealers. These sealers are strippable insuring that, if necessary, can be removed in the future.
Cleaning & Sealing Process
Our Flagstone cleaning process is very aggressive. We use a medium to heavy custom abrasive process to sand away any loose surface to expose fresh stone. During the sanding process the stone is washed with our truck mounted the cleaning equipment. We inspect the surface for layers that are peeling off and need to be removed before the densifier is applied.
Above right: The green arrows show efflorescence blooms in freshly cleaned flagstone. Our penetrating sealers allow the stone to breathe but do not stop efflorescing. The goal is to reduce the corosive minerals ability to damage the stone. Efflorescence occurs when minerals leech up from soil or surrounding rock & leaving a white powder residue behind. This can happen over time or after heavy rains. This is natural & our service does not prevent this.
Unique Two-Part Sealing System: Why Replace when you can Protect?
Exterior flagstone is very susceptible to erosion and spalling. Spalling is when water erodes the bonding molecules that hold the sand particles together and the sandstone starts to peel off in layers (see photos below. If the stone is treated with densifer, spalling might never occur. Once spalling occurs — and it will if the sandstone is exposed to the elements — there is permanent damage that could have been avoided or delayed for decades instead of occurring in years.
Stone Densifier: Unique — We Invented It!
Our goal is to protect and extend the life of you patio so you can enjoy it! The old standard way of sealing flagstone was to apply a penetrating sealer alone. This just wasn’t offering the protection needed in our harsh environment.
We kept seeing heavy erosion on every patio we visited. We didn’t feel good about applying a useless penetrating sealer, knowing it did little good, so we stopped sealing patios altogether. Then Tom did some research and experimenting and came up with our Stone Densifier. After a good amount of testing under the elements, we started offering this treatment in 2010 with great results.
How it works~ Stone Densifier penetrates deep into the stone, rebonds the sand particles and reinforces the bonding molecules already there. It helps to seal the the stone by occupying voids between the sand preventing water from getting in and causing damage. The patio is harder overall and more resistant to chipping and flaking.
After the Stone Densifier we soak in an Enhancing Penetrating sealer to help slow water absorption. This product becomes more effective when used in conjunction with the Stone Densifier. The colors will be slightly enhanced, keeping it very natural looking.