We restore historic sandstone, rubble stone, and fieldstone foundations using breathable lime mortars and hand-cleaning methods. GTA Masonry serves homeowners in Stoney Creek, Hamilton, and nearby areas.
A sandstone foundation is a basement wall built from natural stone blocks before 1930. These old stone walls are not like modern concrete. They are soft and porous. They absorb moisture from the soil and release it as vapor into the basement. This is normal and how they were designed to work. The problem happens when someone repairs them with modern cement. Cement is too hard for soft stone. It traps water inside the block and locks it there. In winter, the trapped water freezes and pushes the stone apart from the inside. This means the block face crumbles into loose sand and gravel. GTA Masonry is a local team of licensed masons. We scrape out hard cement repairs, match the original lime binder, and restore the wall the right way. We serve homeowners in Stoney Creek, Old Town, Stoney Creek Mountain, Winona, and Fruitland. Our team knows how to work with soft stone without damaging it.
Historic masonry is not the same as modern block work. It needs different tools, different materials, and a different approach at every step. Here is what GTA Masonry does to protect your century-old stone.
Hard cement mortar locks moisture inside soft sandstone. We do not use it on historic walls. We mix hydraulic lime mortar that is softer than the stone blocks. Also, this mortar lets moisture travel freely through the wall without getting trapped. This is the only safe repair for pre-1930 stone.
Every old stone wall used a different mix of local sand and lime. If we guess the blend, the new joints will not match in color or texture. We chip out a small piece of original mortar from your wall. Next, we examine the sand grain size and lime type and match both in the new repair batch.
Power grinders running along soft sandstone cut into the block face and destroy the historic ashlar profile. We rake out failing mortar using narrow hand chisels and low-vibration picks. Also, this keeps the stone edges sharp and the original block shape intact.
When a block crumbles completely, it must come out and be replaced. Concrete or poured block patches look wrong and trap moisture in the wall. We contact local quarry suppliers to source natural sandstone that matches your original wall. Next, we hand-fit the replacement block into the course.
GTA Masonry restores historic sandstone, rubble stone, and fieldstone foundations across Stoney Creek and Hamilton. Here are the specific jobs we do.
Mortar joints in a sandstone wall erode from water, root pressure, and salt cycling. We hand-rake the joints to a clean one-inch depth without touching the stone edges. Next, we pack fresh hydraulic lime mortar in thin, compacted layers until the joint is flush.
A block that has crumbled to loose sand cannot hold the wall. We build temporary shoring under the courses above. Next, we remove the failed block and clean the cavity. Also, we set a matching natural sandstone block in the opening using lime mortar.
A rubble stone wall that bows outward needs to be anchored before it falls. We drill horizontal channels through the wall joints and insert stainless steel helical wall ties. Next, we grout the ties in place with lime mortar to hold the wall from shifting further.
Exposed rubble stone cellars collect dust and let in drafts through the open joints. We apply a smooth coat of lime parging over the raw stone face. Also, this coat breathes with the wall, allowing moisture to pass through instead of building up behind it.
Some older fieldstone walls have no concrete footings. They sit directly on compacted soil. When the soil shifts, the wall settles unevenly. We excavate under the wall base in short sections and pour small concrete pad footings. Next, we grout the stone base onto each pad to stop further settling.
Rain water splashes against the stone face and soaks in through the open pores. We spray a clear siloxane water repellent over the dry, finished wall. This sealer blocks liquid rain from entering the stone. Also, it allows internal moisture vapor to escape freely so the wall stays dry.
White powder on a stone wall is called efflorescence. It is mineral salt left behind when groundwater moves through the wall and evaporates. We dry-brush the salt off the surface and clean it with an acid-free solution. Next, we repoint the joints to stop the water movement that causes the staining.
Water pools on the dirt floors of old stone cellars. This keeps the stone base permanently damp. We dig shallow gravel trenches along the interior base of the stone wall. Also, we lay a perforated drain pipe and connect it to a sump basin to pull standing water away from the stone.
Here is exactly what we do from the first day on site to the final protective coat.
We chip out a small section of original mortar from a hidden joint in the wall. We examine the sample under light to identify the sand color, grain size, and lime type used in the original mix.
We rake the failing mortar from each joint using hand chisels and low-vibration pneumatic picks. We dig to a clean depth of one inch. Also, we work carefully to avoid scratching the soft stone face beside each joint.
We remove any crumbled or hollow-sounding blocks and build timber shoring above them. Next, we clean the cavity and set matching natural sandstone blocks back into the wall using the correct lime mortar bed.
Before we start packing mortar, we spray the open joints with clean water. This is an important step. Dry sandstone absorbs water fast. If the stone pulls moisture from the lime mix while it is wet, the mortar cures weak and cracks.
We force the matching hydraulic lime mortar into the open joints using narrow pointing trowels. We apply it in thin passes and compress each layer before adding more. This fills the joint fully without leaving hollow pockets.
Once the mortar reaches a firm, leather-hard state, we run a jointing bar along each joint line to compress and shape the mortar face. Also, we gently wipe excess mortar off the stone block surface with a damp sponge before it hardens.
We wait 28 days for the lime mortar to cure fully before applying any protective coat. Next, we spray a thin layer of clear siloxane sealer over the finished stone wall to repel rain water from the block surface.
We restore historic sandstone, rubble stone, and fieldstone foundations for homeowners and property owners across Stoney Creek and the broader Hamilton region.
Call us to confirm coverage for your home address.
Sandstone is a soft rock held together by natural mineral cement. When hard Portland cement is used to repoint the joints, it locks moisture inside the soft stone. In winter, the trapped water freezes. This expansion breaks the stone face apart from the inside. The block slowly turns back into loose sand and gravel.
Lime mortar is soft, flexible, and breathable. It is weaker than the stone it surrounds, so it takes the damage when the wall moves slightly. Portland cement is rigid and non-breathable. It is stronger than the soft stone beside it, so when stress occurs, the stone face cracks, not the cement. Lime mortar is always the right choice for pre-1930 stone walls.
Yes. Look for white, hard, machine-smooth joint lines between the stones. Old lime mortar joints are softer, slightly rough in texture, and sometimes slightly recessed. Also, if the stones near the joint faces are crumbling or flaking, it usually means hard cement was used at some point.
If your home is listed under the Ontario Heritage Act, visible exterior work on the stone foundation may need approval from the City of Hamilton Heritage Committee. Interior cellar work and below-grade repairs are generally exempt. GTA Masonry helps identify the requirements and submits any needed applications.
A properly matched hydraulic lime mortar repair lasts 40 to 60 years in sheltered wall sections. Joints on south-facing walls and areas below ground-splash level may need fresh work in 25 to 30 years. Keeping gutters clear and maintaining a positive yard grade extends the life of all lime mortar joints.
Yes, but we must remove all the hard cement first. We rake out every cement joint carefully without cutting the stone. Also, we assess each stone for internal freeze damage before packing lime mortar. Stones that have started to crumble behind the joint face must be replaced before repointing.
Efflorescence is a white, powdery mineral salt deposit on your stone wall. It forms when groundwater moves through the stone wall and evaporates at the surface, leaving dissolved salts behind. It is a strong sign that water is regularly passing through your foundation. Repointing the joints and improving drainage stops it.
Yes. Siloxane sealers are breathable and vapor-permeable. They repel liquid rainwater from the stone surface while allowing internal moisture to pass through as vapor. They do not form a film or coating on the surface. Never use rubber paint, epoxy coatings, or plastic sheet membranes on historic soft stone.
Every winter, trapped water in an old sandstone foundation freezes and pushes the stone apart. One hard cement repair accelerates this damage for years. Contact GTA Masonry today to book a free inspection and get a written plan to restore your historic stone wall correctly.
