Masonry Waterproofing in Naperville, IL — Sealing Brick the Right Way

Brick looks like it should be waterproof. It isn't. Every brick wall in Naperville drinks in rain, snowmelt, and wind-driven water, and in a DuPage County winter that absorbed moisture freezes, expands, and pulls the masonry apart from the inside out. Masonry waterproofing in Naperville, IL is how you break that cycle — a breathable penetrating sealer applied to brick and mortar that keeps liquid water out while still letting the wall exhale. Paul Lally's Masonry has been sealing Chicagoland brick since 1988, and we'll say the important part first: done right, over sound mortar, it's one of the best-value things you can do for a brick house. Done wrong, it will ruin the wall.

What masonry waterproofing actually is

Masonry waterproofing is the application of a clear, penetrating sealer — typically a silane/siloxane chemistry — to brick, block, stone, and mortar. It isn't paint. It isn't a coating you can see. It soaks into the pores of the masonry, lines those pores so liquid water beads and runs off, and then visually disappears. The wall looks exactly as it did, just dry.

The critical property is vapor permeability. Masonry always carries some moisture — from the interior of the house, from the ground, from water that finds a way in somewhere else. That moisture has to be able to leave as vapor. A good sealer blocks liquid water coming in while letting vapor pass out.

Why a breathable sealer, and why a film will destroy your brick

Walk into any big-box store and you'll find glossy "waterproofers" that form a film on the surface. On Chicagoland brick, those products are a trap, and here's the exact mechanism:

1. Brick always holds some moisture.
2. A film-forming sealer locks that moisture inside the brick.
3. Winter arrives. The trapped water freezes and expands roughly nine percent.
4. It has nowhere to escape — the film blocks the outward path.
5. So it pushes the hard fired face off the brick. That's spalling, and the sealer that was supposed to protect the wall caused it.

A breathable penetrating sealer does the opposite: it stops wind-driven rain from soaking in, but vapor still leaves, so the brick never becomes a sealed sponge. This is the single most consequential decision in any waterproofing job, and it's why we never put a film-forming product on freeze-thaw-exposed or historic masonry.

Signs your Naperville masonry would benefit from sealing

• Efflorescence — white, chalky salt deposits on the brick face
• Damp or musty interior walls on an exterior-facing wall
• Early spalling — brick faces starting to flake, powder, or pop
• Dark, slow-drying patches on the wall after rain
• Water stains inside near a chimney chase or above windows
• A chimney above the roofline that's never been sealed — the most exposed masonry on any house
• Heavily weather-exposed elevations, typically north and west
• Brick that's already been repointed — sealing after tuckpointing is how you protect the investment

The rule that governs everything: repair first, seal second

This is where most waterproofing jobs go wrong, so we'll be blunt about it. The majority of water entering a brick wall comes through failed mortar joints, not through the face of the brick. A joint that's soft, receded, or cracked is an open channel. Sealer applied over that joint doesn't close the channel; it just coats it and hides it while water keeps running behind.

So the order is non-negotiable:

1. Fix the water paths — repoint failing joints, replace spalled brick, address the lintel, the chimney crown, the coping, the caulking at the window heads.
2. Fix the drainage — gutters, downspout discharge away from the foundation, grade sloping away from the wall.
3. Clean and prep the masonry.
4. Then seal.

If a contractor offers to seal a wall with visibly failing joints and doesn't raise repointing, that's a real warning sign about the rest of the work.

How Paul Lally's Masonry waterproofs a Naperville home

1. Inspect the whole wall system, not just the surface — joints, brick condition, sills, lintels, chimney, coping, grade, and gutters.
2. Tell you honestly whether sealing is the right move, and what has to happen first.
3. Repoint and repair what's failing.
4. Clean the masonry — remove efflorescence, dirt, biological growth, and any old surface residue so the sealer can actually penetrate.
5. Let the wall dry. Sealer applied to damp masonry doesn't penetrate and doesn't perform. This step gets its own time.
6. Protect surroundings — windows, trim, landscaping, hardscape.
7. Apply the penetrating sealer at the correct coverage rate, typically in a saturating wet-on-wet application so the product goes into the masonry rather than sitting on it.
8. Cure and inspect, and walk the finished work with you.

Materials we use

Breathable, penetrating silane/siloxane-based masonry sealers — clear, vapor-permeable, and invisible once cured. Mortar for any repointing is matched for type, color, sand, and joint profile: standard Type N on most residential work, softer mixes on older soft brick, Type S only where structure and exposure genuinely call for it. Never a film-forming coating, never masonry paint, and never a sealer over joints we haven't made sound first.

What drives the cost of masonry waterproofing

• Square footage of wall and how many elevations are involved
• Surface prep — how much cleaning, and whether efflorescence or biological growth has to come off
• Height and access — a two-story elevation or a chimney above the roofline needs ladders or staging
• Repointing scope required before sealing
• Brick porosity — softer, more absorbent brick takes more product
• Site conditions — landscaping, decks, and tight side yards that slow protection and setup

Paul Lally's Masonry gives a free on-site estimate in writing, and we'll tell you plainly if we think sealing isn't what your wall actually needs.

Local context: Naperville brick and DuPage County water

Naperville is unusual in Chicagoland because it spans such a wide range of masonry ages. There's genuine nineteenth-century brick and limestone in and around the historic district and the older streets near downtown, with soft, hand-molded brick and lime-based mortar that demands a gentle approach. Then there's a very large stock of brick and brick-veneer homes from the enormous growth waves of the 1970s through the 2000s — full-masonry fronts, brick chimneys, and stone accents on frame construction.

Those two populations need different treatment. Older Naperville masonry is soft and unforgiving of the wrong product — an aggressive cleaning or a film-forming coating does real damage. Newer brick veneer is harder, but veneer walls depend entirely on the drainage plane behind them, so trapped moisture in a veneer assembly is its own problem.

What they share is DuPage County weather: hard freeze-thaw swings, wet springs, and heavy wind-driven rain from the west and northwest. That's why the west and north elevations are almost always the ones showing efflorescence and early spalling first, and why chimneys — exposed on four sides above the roof — are the most common single thing we're asked to seal.

Related masonry services in Naperville

Waterproofing is the last step, not the first. Most Naperville projects start with tuckpointing and repointing, and often include brick repair, brick replacement for spalled units, chimney repair, limestone and sill repair, caulking and joint sealant, and foundation masonry repair where water is reaching below grade. For whole-house scopes, see residential masonry restoration.

We do the same work nearby — see tuckpointing in Naperville, brick repair in Naperville, and masonry waterproofing in Homer Glen.

Find out whether your brick should be sealed at all

Paul Lally's Masonry Inc. is a family-owned, insured masonry contractor serving Chicago and the Chicagoland suburbs since 1988 — tuckpointing, brick repair and replacement, chimney repair and rebuilds, lintel replacement, masonry restoration, and waterproofing for residential and commercial properties. Built on Craftsmanship. Backed by Experience.

We'll look at the whole wall, tell you what's actually letting water in, and only recommend sealing when it will genuinely help. Our name is on every job we do.

Free on-site estimates — call (708) 448-8866 or request an estimate online.