Building mortared stone walls can add incredible beauty and character to a landscape. With the right materials and techniques, you can create sturdy, attractive stone walls that will last for decades. This guide will walk you through the entire process, from choosing your stones to mixing the mortar to laying each stone. Follow these steps and you’ll have stunning stone walls to enjoy for years to come.
Choosing Materials for Mortared Stone Walls
The first step in building mortared stone walls is selecting your materials. This includes the types of stone, mortar, and any reinforcing materials.
Stone Selection
For stone walls, you’ll want to choose stones that are flat, rectangular, and at least 4-6 inches thick. Good options include:
- Limestone: Durable and weather-resistant, limestone comes in shades of tan, brown, and grey. It has a natural, textured appearance.
- Sandstone: Available in a mix of earth tones like reds, browns, and buff. It has visible grain patterns.
- Fieldstone: These are irregularly shaped stones harvested from fields. They create a natural, rustic look.
- Granite: Extremely hard stones that are grey/pink in color with speckles.
- Bluestone: Dense dark grey or blue-green stones.
Avoid thin or brittle stones as they won’t hold up over time. Mixing stone types and colors creates visual interest and texture.
Mortar
Mortar acts as the “glue” to hold the stones together. Use a Type S or Type N mortar which offer high strength and flexibility. You’ll also need mortar sand. Aim for mortar mixed to a drier, thicker consistency which makes it easier to work with.
Reinforcing Materials
- Metal rebar rods: Insert vertically to reinforce tall walls
- Landscape fabric: Place behind wall to improve drainage
- Crushed stone/gravel: Use as wall drainage fill behind the fabric
Preparing the Base for a Stone Wall
Proper base preparation is key to structural integrity. Here’s how to prep:
Mark Layout and Remove Sod
- Mark the wall layout with stakes and string
- Remove any sod/grass in the base area down to the dirt
Dig Trench
- Dig a trench 12-16 inches wide and 6-8 inches deep
- Extend the trench 6 inches beyond the wall on each end
Add Gravel and Compact
- Fill the trench with 4-6 inches of gravel
- Use a hand tamper or plate compactor to compact firmly
Level with Sand
- Pour 1-2 inches of coarse sand over the gravel
- Rake smooth and level with a board
This provides a solid, stable base for your first course of stones.
Mixing Mortar for Stone Walls
Mix mortar thoroughly before use for maximum bonding strength. Follow these steps:
- Combine mortar and mortar sand in a wheelbarrow or tub
- Mix in water gradually, enough for a firm, stiff consistency
- Let the mortar sit for 5 minutes so ingredients integrate, then re-mix
- Avoid adding too much water as that weakens the mortar
Only mix up what you can use in 30-60 minutes before it starts to set. Discard any unused mortar.
Laying the First Course
Laying the first course well sets the tone for the rest of the wall. Follow best practices:
- Begin at the corner with your largest, flattest stones
- Place stones tightly together, flush on the prepared base
- Use a 4-foot level often to keep this course perfectly level
- Fill any gaps between stones with mortar
- Allow mortar to fully cure before continuing, about 48 hours
The first course is the most important – any mistakes will transfer up the wall. Take your time to do it right.
Setting Additional Courses
Now you’re ready to stack courses up the desired wall height. Here are some tips:
- Choose stones with relatively flat tops and bottoms
- Maintain running bond by centering vertical joints
- Offset seams between stones for strength
- Set stones completely into fresh mortar beds for adhesion
- Push down firmly to squeeze mortar to the surface
- Use pins or shims to maintain level and plumb
- Taper walls inward slightly every few courses
- Remove excess mortar promptly with a trowel for clean joints
Continue this process course-by-course until you reach the desired height.
Capping Off the Top of the Wall
The copings or caps finish and protect the top of stone walls. Materials like:
- Bluestone or granite slabs
- Rectangular cut limestone
- Precast concrete caps
Installation tips:
- Allow the last course to cure fully before capping
- Dry lay caps first for best fit
- Apply mortar to top course, set capstones into place
- Press down firmly, check level and alignment
- Fill joints between caps with mortar
- Smooth excess mortar with a trowel for clean lines
Proper capping completes your wall and ties the whole structure together.
Applying Mortar Joints
Mortar joints give stone walls their finished look. Here are some tips:
- Let mortar cure partially to desired hardness first
- Dampen stone slightly for better adhesion
- Push mortar into joints with a trowel 1/4-1/2 inches deep
- Profile edges for rounded, concave, V, or grapevine shapes
- Brush lightly with a stiff broom for textured appearance
- For very smooth finished joints, sponge and trowel instead
Joint appearance is an aesthetic choice, so experiment to get the style you desire.
Installing Weep Holes and Drainage
Proper drainage and ventilation are crucial for sturdy stone walls. Here’s how to incorporate:
- Place landscape fabric behind wall, covering trench gravel
- Install 4-inch plastic drainage pipes at the base
- Place pipes every 8-10 feet, angled for drainage
- Cover pipe ends with screen to block debris
- Put gravel fill behind fabric, 12 inches or more
- Include vertical weep holes mid-wall lined with mesh
- Weep holes let moisture drain out of wall structure
Follow these steps diligently to allow drainage and air circulation, preventing buildup of excess moisture behind the wall.
Tips for Building Curves in Stone Walls
Curved and serpentine stone walls add artistic elegance to landscapes. To build curves:
- Use flexible materials like plastic edging or bendable metal
- Shape edging to desired curves, pin in place
- Fan out stones at wider curvatures for stability
- Place stones closely on inner curves for support
- Allow more space between stones on outer curves
- Adjust joint thickness and fill gaps as needed
- Take time shaping stones and joints for smooth curves
Focus on quality craftsmanship and your curves will impress.
Troubleshooting Stone Wall Issues
Even with the best construction, stone walls can sometimes develop problems. Here are solutions for common issues:
Leaning or bulging sections
- Disassemble and rebuild with proper base prep and drainage
- Use shims during construction to keep plumb
Crumbling or cracked mortar
- Remove loose mortar and repoint joints
- Ensure mortar mix is workable but not too wet
Stones working loose
- Check for adequate mortar coverage and joint thickness
- Replace loose stones and repoint as needed
Efflorescence or white hazy deposits
- Indicates excess interior moisture, improve drainage
- Brush deposits off once moisture issue is fixed
Plants or moss growing in joints
- Carefully remove all vegetation
- Repoint joints with fresh mortar to fill gaps
- Apply moss killer if needed
Staining or discoloration
- Use masonry cleaner designed for stone
- Test cleaners in an inconspicuous spot first
Address any issues promptly to maintain stability and aesthetics.
Maintaining Stone Walls
Expect minimal maintenance if walls are built well. Follow these care tips:
- Inspect after major storms for any damage
- Look for leaning, bulging, or crumbling
- Check for invasive tree roots or vegetation
- Reapply sealer every 3-5 years
- Clean with gentle stone cleaners only if needed
- Avoid damaging with vehicles, equipment, etc.
- Plant landscaping, vines or shrubs nearby with care
- Prevent soil buildup along the base of the wall
With routine care, stone walls will gracefully withstand decades of use.
Frequently Asked Questions About Building Stone Walls
New stone wall builders often have additional questions. Here are answers to some common FAQs:
How long does it take for mortar to cure?
Allow mortar to cure for 2-3 days before applying weight or additional courses. Full curing takes 28 days.
What color should the mortar be?
Match mortar color to your stones for a seamless look. Natural grey or tan shades usually work well.
How do I keep walls straight and level?
Check every few courses with a 4-foot level. Use shims under low spots and remove shims once mortar cures.
What slope should the wall have?
Build walls sloping back into the bank 1/8-1/4 inches per foot of height. This allows them to resist earth pressures.
How much gravel and drainage do I need?
Use 12 or more inches of gravel backfill behind the wall. Install drains every 8-10 feet.
Can I use river rock for drainage fill?
No, angular crushed gravel packs together for the best drainage. Smooth, rounded rocks compact over time.
How do I keep plants from growing in walls?
If moss or plants take root, remove them fully, improve drainage as needed, and repoint with fresh mortar.
When do I apply sealer to a new wall?
Wait 2-4 weeks for mortar to cure fully before applying any protective sealers to the finished wall.
Conclusion
Building attractive stone walls takes planning, patience, and hard work. But the end results are incredibly rewarding. Improperly constructed walls look sloppy and won’t stand the test of time. By following the techniques outlined here for site prep, drainage, mortar mixing, stone selection, and more, you’ll have professional-quality walls accentuating your landscape for decades to come. Take things course-by-course, use quality materials, and don’t cut corners. Your finished stone wall masterpiece will be something you can proudly enjoy for a lifetime.