Foundation Friday: Case Study: Full-Scope Basement & Garage Foundation Stabilization & Waterproofing

📍 Merrimac, Ma

Built in 1852, this 3,701 sq. ft. Colonial-Victorian home sits along the Merrimack River and blends historic charm with modern living. With a basement-level garage, three fireplaces, and original architectural features, the home had begun to show signs of foundation wear, including mortar deterioration, shifting walls, and moisture intrusion—common in older riverfront properties. This case study outlines how New England Foundation Crack Repair addressed these issues with a comprehensive plan to stabilize the structure, restore compromised masonry, and protect against future water damage.

The Problem: Signs of Structural Weakness and Moisture Infiltration

This property presented several common (but serious) foundation issues that, if left unaddressed, could compromise long-term stability and safety:

• Cracks and crumbling mortar along the basement and garage walls

• Visible shifting and stress in garage foundation walls

• Rusted and improperly supported lally columns

• Moisture signs including efflorescence, dark staining, and air drafts

• Early symptoms of wall bowing in the garage

• Uneven pressure on beams supporting the home’s structure

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The homeowner reached out to New England Foundation Crack Repair for a full onsite evaluation and permanent solution. We quickly confirmed (along with the customer's structural engineer): this was not a cosmetic issue—it was a structural and waterproofing concern that required a multi-phase plan.

Our Approach: A Layered, Structural + Waterproofing Strategy

We developed a comprehensive plan (based on the Structural Engineer's report) to:

1. Stabilize foundation walls from further movement

2. Restore compromised masonry

3. Correct structural support throughout the garage and basement

4. Improve moisture control and long-term protection

Here’s how it all came together:

Basement

Interior Repointing

We started on the main basement side, performing a full interior repoint. This involved:

• Removing deteriorated mortar

• Cleaning joints thoroughly

• Installing fresh, durable mortar mix designed for foundation environments

Why this matters: Repointing reinforces wall strength, eliminates gaps where water and air enter, and protects the structural integrity of your foundation.

We also repointed both interior chimneys in the basement, which had started showing signs of wear. These often-overlooked areas can become moisture entry points and compromise air quality if not properly maintained.

Lally Column Installation

To further stabilize the structure, we installed six lally columns throughout the basement. Each column was set on a properly excavated and reinforced concrete footing to ensure long-term load support.

These steel columns are designed to redistribute weight from the framing above directly into the foundation, providing critical support—especially in areas showing signs of sagging or settlement. This step is essential for improving both safety and structural performance in older homes or those undergoing renovation.entry points if not properly maintained.

Garage Structural Repairs: Lallys, Pillars, and More

The garage side required serious reinforcement due to early-stage wall bowing and outdated support elements.

Step 1: Repoint Garage Walls

We repointed large areas of the garage’s interior walls where shifting and mortar erosion had compromised stability.

Starting to remove the degraded mortar and open the first lally column footing.

Step 2: Install Concrete Support Pillars

To combat wall movement, we installed 4 concrete support pillars, spaced every 3–4 feet. These pillars are designed to:

• Transfer pressure away from bowing areas

• Stabilize large spans of foundation wall

• Prevent progressive deterioration from soil pressure

  
  

  

  Forms for the pillars are almost ready!

  
  

Step 3: Lally Columns For Reinforcement

We removed and replaced 3 lally columns with new steel columns, each resting on properly excavated and poured footings—a crucial detail often skipped by DIYers or less experienced crews.

Additionally, we added 3 more lallys to ensure even load distribution, especially in areas where beams had become unevenly supported over time.

Step 4: Rebuild Access Stairs

To access some of the most compromised sections of wall, we temporarily removed the stairs. Once structural work was complete, we rebuilt them using new lumber, nails, and secure framing techniques.

Moisture Management: Drylok Application

After structural work, we waited 30 days to allow everything to properly cure and settle. Then we applied Drylok waterproofing sealant to the entire basement and garage walls.

Drylok is a high-performance masonry waterproofer that:

• Seals pores in concrete and block

• Prevents moisture seepage

• Helps regulate humidity in basements

• Protects new mortar and reinforcement from early decay

By applying this final layer, we ensure the home is protected both structurally and environmentally.

What Homeowners Can Learn from This Case

If your basement or garage has any of these symptoms, it's time to call an expert:

• Crumbling or missing mortar

• Wall cracks or bulging

• Rusting lally columns

• Uneven or sagging beams

• Water spots, mold, or mineral deposits

• Difficulty closing doors/windows near foundation walls

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Early intervention is not just safer—it’s more cost-effective. Once walls shift or supports fail, the repair process becomes far more involved.

The Final Result: Strength + Protection for the Long Haul With Foundation Stabilization

This project is a prime example of how professional foundation repair is more than just patchwork—it’s strategic, layered, and science-backed.

From interior repointing and structural reinforcement to waterproofing and rebuilding access points, this home is now:

• Structurally secure

• Protected from future moisture damage

• Equipped with modern supports and restored masonry

• Safe for years to come

📞 Ready for a Free Evaluation?

New England Foundation Crack Repair offers expert inspections and long-term solutions for homes across Massachusetts, Connecticut, and Rhode Island.