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CONCRETE WASHING
Concrete washing for Ham Lake and the north metro
Driveways, walks, patios and pavers cleaned evenly with a surface cleaner, on the one surface of your home where real pressure belongs.
Concrete washing removes dirt, organic growth and a winter of salt and sand from driveways, walks, patios, steps and pavers. Glass House pre-treats the growth, cleans with a spinning surface cleaner at 2,000 to 3,500 psi for even, stripe-free passes, then post-treats the slab to even out the tone.
North metro concrete faces dozens of freeze-thaw days and heavy road salt every winter, and that is what scales and pits a slab. Stripping, sanding and sealing are specialty projects that Carson prices in person, because in Minnesota the freeze-thaw winter decides which sealer belongs on your concrete.
HONEST EXPECTATIONS
Porous concrete may need a stronger treatment and may not return to a perfectly uniform finish. We tell you before we begin.
★ Rated 4.9 on Google · 44 reviews
Insured to $2M
Owner-operated
Based in Ham Lake
WINTER ON CONCRETE
Minnesota winters are hard on flatwork
Flatwork (driveways, walks, patios and steps) takes more punishment from freeze, thaw and salt here than it would from a century of sun farther south.
55 to 60
freeze-thaw days in an average Twin Cities snow season. Each one lets water that has soaked into the slab freeze, expand and work deeper.
365,000
tons of road salt applied in the Twin Cities metro each year. De-icers are a large part of why driveways here scale and pit.
2,000+
psi (pounds per square inch) is where we start on concrete, up to 3,500, always with a surface cleaner rather than a bare wand.
2 years
is the minimum age before new concrete is pressure washed. Until then, the answer is not yet.
Sources: University of Minnesota Extension, Twin Cities climatology of freeze-thaw cycles (Mark Seeley, 2026); Minnesota Pollution Control Agency, Chloride.
BEFORE AND AFTER
One patio, one visit
A Glass House job: a patio tucked between the house and the deck, where shade and runoff had stained the whole slab.
BEFORE
Brown and green staining across the slab, heaviest along the walls where water runs off.
AFTER
Cleaned evenly, edge to edge. The crack was already there; a clean surface makes cracks easier to see, so we point them out before we begin.
HOW WE CLEAN CONCRETE
Even, stripe-free and safe for the slab
Concrete is not siding or shingles. It is the one surface where real pressure is correct, provided it is applied evenly and the slab is old enough to take it.
PRESSURE ON CONCRETE ONLY
When we say we never pressure wash, we mean your siding and your roof, which receive a soft wash at low pressure. Concrete is dense enough to take 2,000 to 3,500 psi, and on concrete that pressure is what cleans it properly.
01
Walk it and check its age
Every job starts with a walk-around. Carson looks for cracks, scaling, stains and existing sealer, and confirms the concrete is at least two years old. Sealed or stamped concrete receives a test corner first, so the method is proven on a spot nobody looks at.
02
Pre-treat the growth
A sodium hypochlorite pre-treatment goes on first, so organic growth is killed at the root rather than blasted around. Oil and rust are separate treatments with their own chemistry, handled on request in a fixed order: degreaser first, then the organic wash, then acid last and alone.
03
Surface cleaner, not a wand
A surface cleaner, a round housing with a spinning spray bar inside, lays down even passes at 2,000 to 3,500 psi. A bare wand leaves stripes, and any later sealer magnifies every overlap line, so the wand is kept for edges, steps and detail work.
04
Post-treat and detail the edges
A post-treatment evens out the tone across the whole slab. Curbs, steps, expansion joints and the edges along the house and lawn then receive a final rinse and detail, so the surface dries evenly from edge to edge.
05
Stay off for a few hours
Keep people and cars off cleaned areas for at least 3 hours. After sealing, the wait is up to 96 hours so the coating can cure as well as possible, and vehicles always wait longer than foot traffic, so plan around it.
IDENTIFY BEFORE YOU TREAT
What is on your concrete, and what removes it
Most concrete stains look alike from the street, and the wrong treatment can make some of them permanent. Bleach on rust, for example, sets the stain deeper instead of lifting it.
WHAT YOU SEE
WHAT IT USUALLY IS
WHAT TAKES IT OFF
Orange fans and arcs near sprinklers
Iron from well or irrigation water, tracing the sprinkler throw
Iron stain removal, after the sprinkler is re-aimed
Dark, spreading spots, darker when wet
Oil down in the pores
A degreaser. Acid makes oil worse.
White, crusty bloom on pavers or steps
Efflorescence: mineral salts rising out of the concrete
Efflorescence removal. A rust remover does nothing.
Green or black film in shade
Algae and organic growth
Removed with regular concrete washing
Milky white haze on a sealed surface
Moisture trapped under a sealer
Sometimes a re-melt, often a full strip and reseal
Flaking, pitted surface
Spalling or salt scaling
Cleaning and sealing cannot fix it, and we say so
STRIPPING, SANDING AND SEALING
In Minnesota, freeze-thaw picks the sealer
A sealer decides whether moisture can escape the slab. Chosen wrongly in a freeze-thaw climate, it damages concrete instead of protecting it.
Penetrating sealers breathe
Silane and siloxane sealers soak into the pores and repel water without forming a film on top. They cannot peel, barely change the look, let the slab breathe and usually last 7 to 10 years. For most driveways and exposed flatwork in a freeze-thaw climate, a penetrating sealer is the right answer.
Film sealers can trap moisture
Acrylic, urethane and epoxy sealers sit on top of the slab. Moisture trapped underneath freezes, expands and pushes the film off as peeling, flaking and white blushing, which is how a wet-look driveway that shines in October is lifting by April. Solvent-based acrylics typically need recoating every 2 to 3 years, urethanes every 3 to 5.
Traction on steps and walks
High-gloss film sealers on walkways, steps and pool decks are slick when wet. Anything people walk on receives a matte or satin finish, or an anti-slip additive mixed into the top coat. The additive makes gloss meaningfully safer but not as grippy as bare concrete, so for steps with a real fall risk, matte or penetrating is the recommendation.
Gloss is a commitment
Once a film is on the slab, everything applied later has to be compatible with it, or the whole surface must be stripped first. A wet-look finish enriches the color, and it also shows wear and every imperfection. Choose it knowingly, because a new coat is only as good as the bond beneath it.
Sealing is a 2 to 3 day project, and sealer always goes on in two coats. Glass House uses INSECO products for prep, stripping and sealing, and every sealing job is priced by Carson in person.
HOW PRICING WORKS
Quoted after we see the surface
YOUR CONCRETE JOB AT A GLANCE
QUOTE FIRST
Concrete washing
From $300
Driveways, walks, patios, steps and pavers, surface cleaned
Service Plan member on a Preferred day
From $210
25% member rate, plus 5% on a Preferred day
Rust or oil stain removal
Quoted
Stain-specific chemistry, on request
Stripping, sanding and sealing
In person
A 2 to 3 day project, priced by Carson in person
Concrete under 2 years old
Not yet
Pressure washing waits until the slab has cured
Every slab is different
From $300
Starting at $300. Concrete washing is quoted after Carson sees the surface, its age and what is on it. Stripping, sanding and sealing are priced by Carson in person, only, because the preparation and the weather window determine the job.
WAYS TO SAVE
Service Plan members
25% off any other work, holiday lighting included
Veterans
10% off any service
Same-day neighbors
15% off for both households
Preferred day
Another 5% off on top of any other saving, up to 25% in all
Seniors 65 and older
$50 off
Three projects together
10% off
Discounts don't combine — you receive whichever single saving is largest. Then a Preferred day can take another 5% off, up to 25% in all (Service Plan members aren't capped).
This season’s flash sale is shown at the foot of every page.
GUARANTEES
What backs the work, word for word
These are printed word for word on your quote, your work order and your invoice.
INCLUDED
Workmanship Standard
If we miss an area or leave normal cleanable residue, tell us and we'll re-clean or touch it up. Our guarantees cover the cleaning result — not repairs, replacements, permanent stains, or conditions that can't be safely corrected through cleaning.
WHAT IS INCLUDED
What concrete washing includes, and what it does not
Concrete is the one surface that receives real pressure, and even then it is controlled. A concrete wash covers the following.
INCLUDED
In every concrete wash
• Driveways, walks, patios, steps and pavers
• A pre-treatment that kills organic growth
• Even surface cleaner passes, with no wand stripes
• A post-treatment that evens out the tone
• Edges, curbs and expansion joints rinsed and detailed
NOT INCLUDED
Quoted separately, or not something we do
• Concrete under two years old, which pressure would permanently etch
• Oil, rust, iron, efflorescence, paint and graffiti stains
• Stripping, sanding and sealing, priced by Carson in person
• Repairing cracks, spalling and pitting
• A perfectly uniform finish on older, porous surfaces
EQUIPMENT AND METHODS
A surface cleaner, not a bare wand
Sodium hypochlorite and a spinning surface cleaner at 2,000 to 3,500 psi, high flow. Together they clean the surface, kill organic growth and leave an even finish without etching the concrete. Sealed or stamped concrete receives a test corner first. A heated machine is available on special request for oil, because heat thins oil and draws it out of the pores; it does not come to most jobs.
SAFETY AND CARE
Safe for the slab, the lawn and your family
Concrete is the one surface where real pressure belongs, which makes it the one where discipline matters most.
THE SLAB
Never under two years old
We do not clean concrete that is less than two years old, and no one should. Green concrete, meaning concrete that has not finished curing, will be permanently etched by pressure. If a slab is newer than that, the answer is not yet, and that is a complete answer.
THE TONE
An even color, edge to edge
Sodium hypochlorite can discolor concrete, sometimes unevenly, which is why every wash ends with a post-treatment to even the tone. If tinting does appear, the fix is re-cleaning the whole slab uniformly so the color matches, or oxalic acid where the tint is mineral-based, such as rust and iron.
YOUR LAWN
Runoff diluted and redirected
Wash water is diluted heavily and steered away from lawns and beds as far as the site allows, and nearby plants are rinsed before and after the wash. Overspray that lands on a pre-wet leaf is diluted to the point of being harmless, which is why landscaping survives.
CHEMISTRY
Bleach and acid never meet
Bleach-based cleaners and acidic rust removers are never mixed and never used back to back without a full rinse and dry in between, because together they release chlorine gas. Acid work is done in rubber gloves, a respirator and safety glasses. It is also why a homeowner should never follow a bleach wash with a rust remover.
THE OWNER
The first surface you touch coming home
Glass House is owned and run by Carson Brenny. He grew up in Ham Lake, went to Blaine High School and has worked full-time in exterior cleaning since 2020. He quotes your concrete, runs the surface cleaner himself and walks the finished slab with you before the job is done.
A driveway, a front walk and a patio are the first things a family and its guests touch on the way home. Concrete is also where the costliest mistakes happen, from wand stripes to etching to rust set by the wrong cleaner, so Carson tests, explains and works carefully rather than rushing a slab.
IN CARSON'S WORDS
“It's my neighbors' homes: their biggest investment, one of the places they spend the most time, and where the people they care about most live. It's something everyone should enjoy, and I believe that.”
Carson Brenny, owner
✓
Surface cleaner for an even finish
✓
Test spots before any stain work
✓
Clear about what will and will not come out
BEFORE YOU CALL
Three quick tests for your concrete
Each test takes a minute, and together they answer the questions Carson asks before quoting any sealing work.
01
The water droplet test
Put a little water on the surface. If it soaks in and darkens the concrete, the slab is not sealed. If it beads up, a sealer is present. The test takes ten seconds and tells us more about the surface than a photograph does.
THE EASIEST TEST OF ALL
Ask around the house first. The bucket from the last sealer is often still in the garage, or the invoice is in a drawer, and either one tells us exactly what is on the slab. If no one knows, we test rather than guess.
02
The hose test
Wet a section and look at it. If you prefer the darker, richer color, a wet-look sealer gives roughly that appearance. If you prefer the concrete as it looks dry, a matte or penetrating sealer protects it without changing the look.
03
The flake test
Look for anything peeling, flaking or milky white. Any of those means the old sealer is failing, and a new coat over it would come off with it the next spring. That calls for stripping first, and a small test strip shows how many applications the job will take.
SEALING LIMITS
Sealing these would make the problem permanent
Concrete under 28 days old
Moisture and free lime are still working their way out of new concrete. Seal it now and they are trapped under the film, where they cause blushing, efflorescence and peeling. No product gets around this. It is a separate clock from the two-year rule for pressure washing.
A slab with a moisture problem
Persistent dark, damp patches mean water is coming up from below, often where there is no vapor barrier. A sealer traps that water and fails. The same goes for any surface that does not drain, because standing water finds its way under a film.
Spalling or salt-scaled concrete
Salt-scaled driveways are common across the north metro. A sealer does not fix failing concrete; it locks the damage under a clear coat, and afterward it looks as though the sealer caused it. Spalling calls for a concrete contractor, not a coating.
Oil that will not come out
Sealer will not bond to oil. Seal over an active stain and the result is fisheyes, dull spots and peeling directly over it, with the oil now trapped under a coating. If a stain will not clean, it will not bond, so oil comes out first or the area is not sealed.
Efflorescence still on the surface
Efflorescence is the white, chalky bloom of mineral salts rising out of concrete or pavers. Seal over it and the bloom is under glass for good, so it comes off first. New pavers are given a season for efflorescence to work its way out before any sealer goes down.
A like-new finish on worn concrete
A sealer enhances what is there; it does not create what is not. On a worn-out slab, a like-new driveway is an expectation no coating can meet, so Carson resets that expectation before any work is quoted, or recommends against sealing.
MINNESOTA TIMING
When to wash, and when to seal
SPRING
Wash off the winter
Salt, sand and winter grime come off. It is also the time to check for new scaling before anything is sealed.
SUMMER
Prime sealing weather
Warm, dry stretches let coatings cure. A slab is never sealed while damp or with rain in the forecast, because moisture at seal time is what makes a seal fail.
FALL
The window closes
Cold nights and heavy morning dew are how a fresh seal turns milky. Surface temperature and dew point decide the date, and a marginal late job is better booked for spring.
WINTER
No washing
Water turns to ice on frozen concrete, so exterior washing pauses. Our exterior season runs March 1 through November 15.
A bad seal job looks perfect in October and terrible in April. Our winter is the test, which is why prep, moisture and the weather window matter more here than they do farther south.
WHERE WE WORK
Concrete washing across the north metro
Glass House is based in Ham Lake and cleans driveways, walks, patios and pavers throughout Anoka County and the Twin Cities north metro.
Each city page covers the local conditions that affect your concrete. The surrounding north metro is served as well, and we travel farther for a small trip fee.
CONCRETE QUESTIONS
Concrete washing FAQ
Will pressure washing damage my concrete?
Not when it is done correctly. A spinning surface cleaner lays down even passes at 2,000 to 3,500 psi, so there are no wand stripes and no etching. Glass House never pressure washes concrete that is less than two years old, because a slab that has not finished curing will etch permanently, and sealed or stamped concrete is tested on a corner first.
Can you get oil stains out of my driveway?
Often, and the age of the stain decides how far. Concrete is full of tiny capillaries that draw oil down and outward, so a wash cleans the surface while oil below can rise back up as a shadow. Fresh spills usually come out completely and recent stains nearly so. Old, soaked-in stains improve substantially but may leave a shadow, and more than one application is normal.
Can you remove rust from my driveway?
Yes, with iron-specific chemistry, starting with a spot test. Bleach sets rust rather than removing it, which is why reaching for bleach usually makes the stain worse. Before treating, we make sure the sprinkler that caused it has been re-aimed, or the rust comes back. Iron left long enough bonds to the surface permanently, so the sooner it is treated, the better.
Should I seal my driveway?
Often, yes, and usually with a penetrating sealer. It soaks into the concrete instead of forming a film, so it breathes, cannot peel and holds up to freeze-thaw far better, typically lasting 7 to 10 years. Carson looks at the slab, its age and any previous sealer before recommending anything, and he prices sealing in person.
Why is my sealed concrete turning white?
Usually moisture is trapped under a sealer that could not breathe, went on too heavily or went on too late in the fall, when cold nights and dew arrived before it cured. A solvent can sometimes re-melt a solvent-based acrylic and release the moisture, but often the sealer has to be stripped and the surface redone.
How long does sealing take?
Plan on 2 to 3 days, with cleaning, prep and cure time between the two coats, then up to 96 hours before heavy use. Vehicles always wait longer than foot traffic. Carson gives you the exact plan with the quote, so the household can arrange parking and access ahead of time.
What should I do with a fresh oil spill?
Act within the first hour, because the clock matters more than the product. Cover the spill with non-clumping clay cat litter or oil-dry, grind it into the surface underfoot so it reaches the oil in the pores, leave it an hour or overnight, then sweep it up and follow with a degreaser.
Can you fix cracked or flaking concrete?
No. Cleaning and sealing cannot repair cracks, spalling or salt scaling, and sealing over them only locks the damage under a coating. Glass House is a cleaning service, not a repair service, so Carson will tell you plainly when a slab needs a concrete contractor instead of a wash or a seal.
