What is Glazed Creosote?

glazed creosoteSoot isn’t all that builds up in the chimney from your woodburning fireplace. Creosote is a chemical compound that’s created when condensation interacts with smoke. It also builds up in the chimney. It can become a major hazard if it hardens into glazed creosote.

What is Glazed Creosote?

When wood burns, the smoke produced contains many different gases and particles like carbon monoxide and ash. As they move up through the chimney, condensation interacts with these byproducts producing creosote which builds up along the chimney walls. In the early stage of creosote build-up, it is flaky and easy to remove like soot. If it isn’t removed, it can progress to the second stage when it becomes sticky and tar-like. The third and final stage of creosote buildup is glazed creosote. It reaches this stage when there is enough creosote built up in the chimney to reduce airflow through the flue.

Creosote is flammable during all three stages, but glazed creosote is the most dangerous. If a stray spark ignites glazed creosote deposits, the fire can burn at high temperatures for a long time. This can cause serious structural damage to your chimney or spread to your home.

How to Remove Glazed Creosote

Glazed creosote is tough to remove. We have seen amateurs try to get rid of it with chains, chisels, and other heavy-duty tools that damage the chimney liner in the process. Using a fireplace with a damaged chimney liner can be as dangerous as a chimney lined with glazed creosote. Professionals get rid of glazed creosote by using industrial-grade creosote remover that will not damage the chimney liner. They spray or brush the remover onto the glazed creosote. Once it is absorbed, the creosote will begin to soften and flake until all of it can be brushed off and vacuumed out.

How to Prevent Glazed Creosote

Even though glazed creosote can be removed by a professional, stopping creosote from getting to that stage is the best way to prevent a chimney fire. There are two steps you can take to avoid third stage creosote:

Step 1: Only burn seasoned firewood.Chimney sweep in Middletown MD

Burning paper, cardboard, trash, or other flammable materials besides wood will accelerate creosote buildup because they produce more chemical byproducts as they burn. Green or unseasoned firewood also produces more chemical byproducts when burned. If you only burn seasoned firewood, less creosote will build up in the chimney during burning season.

Step 2: Schedule annual chimney cleanings.

Scheduling a chimney cleaning every spring, after using the fireplace in the winter, will prevent creosote from building up year after year. If you schedule a cleaning once a year, it is unlikely the creosote in your chimney will reach the third stage. It will also open up the airway in your chimney so that your fireplace functions properly next winter.


Need to schedule a chimney cleaning this year? Give High’s Chimney Service a call! Our team of CSIA- and CCP-certified chimney technicians serve residents throughout Virginia, Maryland, and Washington, DC. Call 703-550-5115 or 301-519-3500


Chimney Anatomy: What You Need to Know

To look at a chimney, it doesn’t appear that very much is going on. It’s just a vent system that allows smoke to leave the firebox and be sent into the outside air. This is a good description of how chimneys work. But for them to work efficiently and safely, many components must conspire and work together correctly. Here is an overview of basic chimney anatomy.

Chimney damper

Chimney dampers are located just above the firebox and have an open and closed function to regulate air flow. There are also top-sealing dampers that go on the top of the chimney. Dampers must be fully open during a fire to produce the correct amount of air flow and drafting. When the fireplace is not in use, chimney dampers should be sealed tightly shut to prevent the transfer between interior and exterior air as well as to keep possible debris and small animals from entering the home.

Smoke shelf

Located between the firebox and smoke chamber (see below), the smoke shelf’s job is to collect any rainwater or debris that may have entered the chimney. The smoke shelf also helps to prevent downdrafts from sending smoke and toxins into your home.

Smoke chamber

The smoke chamber is found just above the damper and smoke shelf and acts as a conduit for taking smoke from the firebox up into the chimney. The surfaces of the smoke chamber should be smooth to allow efficient drafting. If surfaces become rough with age, drafting can be impaired and excess flammable creosote can begin to build up, further hampering drafting. It is estimated that about 60% of chimney fires start in the smoke chamber.

Chimney flue

The flue is the inside of the chimney, the narrow vent path running from the smoke chamber to the outside of the home. For safety, many flues contain chimney liners, or flue liners, to channel smoke out of the home and protect the masonry of the chimney from dampness, acids and intense heat.

Chimney liner

The majority of chimney liners are made from aluminum, stainless steel, clay tiles or poured-in-place masonry. A clean liner that’s in good repair will efficiently vent smoke and toxins out of your firebox and into the outside air. Damaged liners can lead to a chimney fire and the decomposition of the bricks and mortar that make up the chimney. Damaged liners also are more likely to hold buildups of creosote, which can ignite and start a fire.

Chimney chase top

Chase tops serve as a protection against rain and moisture. These components usually are standard equipment for factory-built chimneys and are rarely seen on masonry chimneys.

Chimney Repair in Germantown MDChimney crown

Chimney crowns are cement structures that serve as a top covering for masonry chimneys, sealing off the entire area except for the flue pipes. Chimney crowns protect the chimney’s bricks and mortar from rain damage.

Chimney cap

The chimney cap sits atop the chimney and acts as a guard against rainwater as well as infiltration by various debris including twigs and leaves from nearby trees as well as small animals like squirrels and rodents, who like to build nests inside chimneys. Chimney caps have mesh sides, which allow smoke to draft while keeping outside elements outside where they belong.

As you can see, chimneys and their components all work together to allow you to operate your fireplace safely and confidently year after year. The only way to ensure that your chimney is in tip-top shape is to schedule yearly inspections and cleaning from a CSIA-certified chimney sweep.

If it’s time for a thorough inspection or cleaning for your chimney, contact Highs Chimney Service of Gaithersburg, MD, at (301) 519-3500. Our only goal is your complete satisfaction and safety.


Common Issues When Connecting New Gas Appliances to Older Chimneys

gas applianceCommon Issues When Connecting New Gas Appliances to Older Chimneys
Home-heating appliances like means a chimney or vent pipe.
For drafting to work right, the problems are bound to occur. This is all very relevant when connecting gas heating appliances such as stoves and fireplaces to older, existing chimneys. Just because a chimney is a “vent system” doesn’t mean it’s ideal for the new appliance.Incompatibility in this hookup sluggishly. Let’s look at both problems.

Dangerous chemicals within the flue

When the connector pipe on the new gas appliance is too small for the chimney flue, every time combustion happens, overproduction of acids and other chemicals will occur. Once example is the creation of hydrochloric acid that happens when chlorides in the air come into contact with condensation inside the flue. The result – either sooner or later – will be erosion of the chimney liner and areas of the masonry.

It’s bad enough to have this environment inside the flue. Worse is when hampered air flow causes combustion chemicals including deadly carbon monoxide (CO) to backdraft down into the home. CO is invisible and odorless, which means people can be poisoned by it before they realize they’re breathing it in.

Problems with air flowgas stove

A proper draft system will pull smoke and toxins up away from the firebox and channel them to the outside. When a gas appliance and existing chimney are improperly sized for one another, as noted, toxins produced through fuel combustion can flow backwards into the home.

The reason this happens, ironically, is because of the high efficiency of modern gas appliances. For example, gas fireplaces and stoves send the majority of their heat into the home, rather than up the chimney. If the flue is too large for the gas appliance, not enough heat will move up it to warm (lighten) the denser cold air high in the chimney. This makes it difficult for the lower volume of lighter combustion air to move up and out of the flue.

For these reasons, it’s very important to have your new gas appliance installed only by a certified chimney professional. This individual will thoroughly inspect the existing chimney and make any necessary modifications to ensure that proper drafting is achieved. Connecting a new gas-fueled appliance to a chimney designed to draft wood smoke is never a job for a novice.

Chimney damage signs

If you’ve been running a gas appliance through an existing chimney not specifically built for the appliance, signs of chimney damage you may notice include:

• Exterior chimney masonry that is discolored

• Blistering/bubbling paint on interior walls of the home

• Crumbling chimney bricks and mortar

Ceiling staining

• Interior or exterior walls that are damp or wet to the touch

• Peeling wallpaper

Any of these signs of chimney damage warrant immediate service from a certified chimney technician before you use your gas appliance again. High’s Chimney Service of Gaithersburg, MD, is ready to help with inspection and installation of your new gas appliance, no matter what type of vent system you’re connecting it to. Count on us to do the job right and ensure the safety of you and your family. Call (301) 519-3500 to arrange a service call or to get your questions answered.


Preventative Maintenance Cuts Chimney Repair Costs

fireplace draft issues in Chevy Chase MDLiving in a home with a fireplace is a big perk especially here on the east coast. On dark winter evenings, it’s a pleasure to relax next to a crackling fire in the hearth. Unfortunately, your fireplace’s chimney could become a costly expense if it isn’t maintained. Investing a little now in preventative chimney maintenance can save you thousands of dollars in future repairs.

Your home’s chimney is battered by high winds, heavy rainfall, and driving snow. Even though it’s built to last for decades, it is still vulnerable to damage, especially from water intrusion. A leaking chimney is one of the most common problems that chimney sweeps are requested to fix. Repairing water damage to your chimney and surrounding walls, ceilings, and support beams can be extremely expensive.

Critter problems in the chimney are almost as common as water problems. Many animals love to make their homes in them increasing the likelihood of a chimney fire. They can also attract other pests like insects to your home or bring in diseases.

There are 4 inexpensive preventative maintenance steps that you can take to avoid costly chimney repairs.

#1 – Waterproof the Masonry & Seal the Chimney Crown

Water is the leading cause of chimney damage. It can lead to structural damage to the chimney and ruined drywall, ceilings, floorings or structural beams in your home. One of the ways that water gets in is by seeping into the masonry or through cracks in the chimney crown.

Bricks, mortar, and concrete that haven’t been treated with a waterproofing sealant absorb water. When the water in the masonry freezes and thaws, during chilly months, it expands and contracts. This can cause cracks and breaks. Eventually, it can weaken the structure of the chimney. You can prevent this by treating the masonry with a waterproofing sealant and the chimney crown with a waterproofing sealant that also fills in any small cracks.

#2 – Treat the Chimney Flashing

Flashing is the metal seal that bridges the gap between the chimney and the roof. It prevents precipitation from slipping in between the two structures. Most chimney leaks are caused by deteriorated flashing. Treating the flashing with waterproofing sealant prevents deterioration and extends its life.

chimney maintenance maryland

#3 – Have a Chimney Cap Installed

A chimney cap has two important jobs: prevent animals and precipitation from getting into the chimney. It is a metal cap that covers the opening at the top of the chimney so that rain, sleet, and snow can’t fall straight down the chimney. It typically has wire mesh around the side to prevent critters from crawling or flying into the mouth of the chimney.

#4 – Schedule an Annual Inspection & Cleaning

Creosote is a dangerously flammable chemical compound that builds up in chimneys. It’s the result of condensation in the chimney that mixes with soot and other combustion byproducts. It is the leading cause of chimney fires. Removing it yourself, without experience and specialized equipment, is difficult. CSIA-certified chimney sweeps have the training, experience, and equipment to clean it out and prevent the risk of a house fire.

Fire safety and chimney experts agree that an annual chimney cleaning is the most important step you can take to prevent a house fire sparked by your fireplace. During the cleaning, a professional chimney sweep will also perform an annual inspection. Their training and experience equip them to notice potential chimney problems that you could easily overlook. Diagnosing and fixing small problems found early during an annual inspection is the best way to prevent them from becoming big, expensive issues.

Are you ready to protect your chimney? Give us a call to learn more about the preventative maintenance services that we can provide! Our CSIA- and CCP-certified chimney technicians are experts in chimney maintenance, cleaning, and inspections.

High’s Chimney / (301) 519-3500

Why and How to Minimize Creosote Buildup in your Chimney

House FireChimney fires can be deadly. Even though chimneys are designed to withstand high temperatures and stop a fire from spreading to your home, they can fail if creosote in your chimney catches fire. Creosote is a highly flammable chemical compound that builds up in your chimney. A stray spark or high temperature in your chimney can ignite it. Chimney fires fueled by creosote can get to up to 2,000 degrees Fahrenheit. This can cause the chimney liner to crack and allow flames to spread to your home.

What is Creosote?

Smoke from a wood burning fire contains wood particles, gases, and other chemical compounds. As these combustion byproducts cool on their way up the chimney, they condense along the chimney walls. This condensation is what turns into creosote.

Creosote is extremely flammable. As it builds up, it passes through three stages. Each progressive stage is harder to remove than the last.

First Stage Creosote

When creosote forms, in the first stage, it is flaky and easy to remove. Professionals can quickly get rid of it with a basic chimney brush.

Second Stage Creosote

As more creosote builds up, it changes. It thickens and hardens into a shiny, glass-like compound that can’t be removed with a brush. Second stage creosote requires professional removal. CSIA-certified chimney sweeps typically use a power drill with a rotary loop to remove it.

Third Stage Creosote

If creosote continues to build up in a chimney, it moves on to a third stage. Third stage creosote is a thick, sticky tar-like substance. It is the most flammable at this point. It is practically a concentrated fuel. Third stage creosote also required professional removal by a CSIA-certified chimney sweep. In most cases, professional grade chemicals will be used to remove it. In severe cases of extreme buildup, it may be necessary to remove and replace the chimney liner.

You can prevent creosote buildup from reaching the third stage or causing a chimney fire by following the best practices recommended by the NFPA.

Creosote in ChimneyHow to Minimize Creosote Buildup & Prevent a Chimney Fire

The National Fire Protection Association (NFPA) is a nonprofit organization that was founded in 1896 to help prevent house fires. They develop safety codes and best practices to reduce fires based off of their research. They are an authority on how to minimize creosote buildup and prevent chimney fires. Here are there top recommendations:

  1. Only burn dry, seasoned firewood.
    Freshly cut wood is packed with moisture that makes it difficult to burn and produces dense black smoke filled with combustion byproducts. Allowing firewood to season, or dry out for at least six months, helps it to burn completely and produce less smoke.
  2. Never burn artificial logs.
    Artificial logs produce more combustion byproducts than regular wood which significantly increases creosote buildup.
  3. Build hot, clean burning fires.
    Stacking firewood with enough space between the logs for oxygen to circulate will produce a hotter, cleaner burning fire. If you consistently build efficient fires like this, less creosote will build up in your chimney because your fires will produce less smoke.
  4. Make sure the fire gets enough oxygen.
    Open the damper in your fireplace before you light a fire to ensure it will get enough oxygen. If your fireplace has glass doors, it is a good idea to leave them cracked open slightly so that air can circulate.
  5. Reduce condensation by warming up a cold flue.
    If your chimney isn’t well insulated, the flue can reach low temperatures. Lighting up your fireplace when the flue is cold will create more condensation and larger creosote deposits. You can easily warm up the chimney by rolling newspaper up to make a torch, lighting it and holding it up in the chimney. When you notice the smoke from the torch rising straight up, you’ll know that the flue is warm enough.
  6. Schedule an annual chimney cleaning and inspection.
    The NFPA recommends an annual chimney inspection and cleaning because they have found that it is the most effective way to reduce the risk of a chimney fire. Professional chimney sweeps are trained to spot issues in your chimney that may pose a safety risk or increase creosote buildup. We also have the tools and training to safely and efficiently remove creosote.

Following these six recommendations will help you protect your home from a dangerous chimney fire. If you are looking for professional chimney cleaners that you can trust, give us a call at High’s Chimney Service. Our CSIA- and CCP-certified chimney technicians serve residents in Maryland, Virginia and Washington, DC.

Fireplace Cleaning Tips for Your Spring Cleaning Chore List

Fireplace and chimney cleaning are very important in keeping your appliance looking good, running safely and operating at peak efficiency. You can do some cleaning tasks yourself; others are best handled by a professional chimney sweep. Let’s take a look.

Do it yourself

Glass fireplace doors: If your fireplace doors are smudgy and unsightly, you can use a household window cleaning solution and paper towels to remove the buildup and make the glass shine again.

Fireplace Spring CleaningInside the firebox: This is a two-step process: first, shovel or vacuum out the ashes and small wood chips, then use a mixture of warm water and dish soap with cleaning rags to remove soot buildup on the inner surfaces of the firebox. Gas-burning fireplaces require only basic cleaning and wiping down with soapy water.

Cleaning the surround: If you have a surround made of brick, tile, rock or other material, you may notice some discoloration proximal to the opening of the fireplace. This is normal smoke stain and can be cleaned with soap and water. For all surface cleaning in and around the fireplace, you can purchase specially formulated cleaners at your local hearth store or most hardware stores.

Chimney sweep services

When you get deeper into your fireplace and chimney system, most cleaning tasks are best performed by chimney sweeps, who have the training and tools to do the job safely and correctly.

Fireplace damper: Over time, dampers become coated with soot and smoke byproducts and can stop functioning properly. When a certified chimney technician cleans your damper, a thorough inspection of the device also will be performed to spot signs of damage and ensure the seal is tight.

Cleaning the flue: Wood-burning fireplaces create a substance known as creosote when in operation. Creosote is sicky and flammable. If regular chimney cleaning isn’t performed, it can build up in the flue and lead to two serious problems:

  1. Chimney fire
  2. Air-flow obstructions

Both problems should always be avoided and, fortunately, with annual chimney inspections and cleanings, they will be.

Once inside a chimney, creosote can present as a soft, sticky substance, but it also can turn hard and slate-like, making it very difficult for the average homeowner to remove. Professional chimney technicians have special tools to break up solid creosote and thoroughly remove it from your flue without damaging the chimney.

Inspection during cleaning

Not only do chimney pros have the tools and skills required to clean creosote and obstructions (twigs, leaves, animal nests, etc.) from your chimney, they also have the expertise to inspect your fireplace system for early signs of damage. Areas and components covered during an annual inspection include:

Chimney Damage and RepairChimney crown – check for cracking/deterioration

Chimney cap – make sure mesh is intact and the device is securely mounted

Exterior masonry – inspect for cracks in bricks and mortar and areas of decomposition

Chimney flashing – check for warped or missing sections

Chimney liner – ensure the liner is sound and undamaged

Interior masonry – make sure no damage exists from chimney fires or long-term moisture

These and other parts of your chimney can be repaired, rebuilt or replaced, as needed.

Spring is a great time to work together with a chimney services professional to get your fireplace and chimney in clean, tip-top shape for the coming season. High’s Chimney Service of Gaithersburg, MD, is ready to help with all chimney cleaning, inspection and repair tasks. Schedule an appointment, or get your questions answered at (301) 519-3500.

Protect Chimney with Water Repellent This Spring

Chimney Cracks InspectionOne of the best ways to prolong the life of your chimney is to have it professionally sealed with a high-quality water repellent. As chimneys age, small cracks can begin to appear in the bricks and mortar joints, which will allow water to get in. Once inside, water begins to damage the chimney structure, leading to an unsafe operating environment and costly repairs.

Here in Maryland, our cold winters are hard on chimneys. Any chimney with even a small leak is susceptible to further damage when water freezes within cracks and then expands, making larger cracked areas for more water to infiltrate. The solution in most cases is professionally applied water repellent.

What is chimney water repellent?

There are several types of spray-on water repellent. Some are water-based, others are solvent-based. Your certified chimney services technician will know which is the best type to use based on the condition of your chimney.

The top water repellent products are vapor-permeable, which means they’re able to release water vapors that otherwise could pass into the bricks when the chimney is being used. With a good repellent, you’ll prevent 99.9% of water penetration into the bricks. When you have your chimney sealed, it’s actually better in some ways than a brand-new chimney.

Benefits of using a top-line water repellent on your chimney

  • Save big money on future repairs to fix water-damaged masonry
  • Keep your chimney in a safe operating condition
  • Say goodbye to damage from freeze/thaw cycles
  • Most repellents are environmentally friendly
  • Coating resists fungus and mildew
  • Coating protects against efflorescence (water staining)
  • Maintains the natural look of your chimney (not a glossy finish)
  • 10-year warranty when properly applied

How chimney water repellent is applied

In most cases, your chimney service expert will choose a water-based repellent. If your chimney has been sealed in the past, often a solvent-based coating will be used for added strength.

Prior to application, the external surfaces of the chimney will be thoroughly brushed and cleaned to allow for maximum adherence of the sealant. At this time, areas of brick and mortar that need repair will be addressed. The product is then sprayed on in the correct volume to create a solid seal.

Why have a professional do the job?

Highs Chimney ProfessionalsIn addition to ensuring that your chimney is properly prepared for the seal coating and applying the repellent in accord with manufacturer’s exact specifications, it pays to have a certified chimney technician perform this work for other reasons.

Chimney’s need regular inspections and occasional repair work to keep them running at the highest safety and efficiency levels. In fact, virtually every fire-safety organization in the U.S. recommends annual chimney inspections and cleanings.

Your chimney technician can perform a thorough inspection while on the service call to add water repellent. This inspection can turn up issues within the chimney structure that need to be fixed to prevent extensive damage down the line.

A spray-coating job can be done in conjunction with a complete chimney cleaning to remove flammable creosote from the flue. Excess creosote, which forms when wood is burned, is the primary cause of chimney fires in America.

You want your fireplace and chimney to be safe and highly efficient. So do we. If it’s time to have your chimney seal-coated with a strong water repellent, or if you need your system inspected or cleaned, High’s Chimney Service of Gaithersburg, MD, is ready to help. To arrange for a service call, or to get your questions answered, reach us at (301) 519-3500.

Selective Hauling

schedule a chimney service appointment todayThank you, Selective Hauling for this article on our services.  Selective Hauling has been a valued partner for 10 years now and we appreciate their punctuality and efficiency.  Our partnership has been a natural success, as both of our companies serve our clients with superior service.

Here is a look at the article that Selective Hauling wrote about us:

“Having been in business since 2003, we have gained many valued clients and friends through serving each other’s mutual needs.  Every so often, we like to take a moment to share a story about how important each client is to us.  One such customer is High’s Chimney, located just down the street from us in Gaithersburg, Maryland.  We have been serving High’s Chimney with a dumpster rental on their lot since 2008!

High’s Chimney is a premier chimney sweep in Washington, DC and its surrounding areas.  They treat their own customers with care, efficiency, and safety.  We can appreciate their attention to detail and ability to achieve success on their projects.

High’s Chimney can also take care of your air duct cleaning and chimney repair.  If you haven’t had your chimney, attic or crawl space inspected recently, they can take care of that too!

Their website offers plenty of tips on care and maintenance of your chimney, including how to waterproof or block your chimney.  Be sure to check out their Facebook page for more tips and ideas for your fireplace.

We would like to thank High’s Chimney for their loyalty!”

It’s been a great 10 years, and we look forward to many more as a partner with Selective Hauling.  If you are replacing your fireplace or completing a home renovation and need a dumpster rental or bulk trash removal in the Washington, DC area, be sure to give Selective Hauling a call!

Do Dryers Really Cause House Fires?

dryer vent cleaning fairfax county vaDid you know that dryer vents can cause house fires? At High’s Chimney, it is important to our company to educate our clients to help protect their property through our repair and preventative services. When it comes to your dryer, it is vital to properly clean the vents to prevent future property damage. On average, there are an estimated 2,900 home fires reported each year that are caused by dryer vents. Within the same average of 2,900 house fires each year, there is also an estimated five deaths, 100 injuries, and 35 million dollars accumulated in property loss.

In addition, on average 34% of home clothes dryer fires are caused by failure to clean the dryer. These statistics prove how vital proper maintenance and preventative services are to the safety of your home. Our professional chimney specialists recommend cleaning the lint filter before and after each load of laundry. We also suggest cleaning the lint filter with a nylon brush at least every six months to help relieve congestion. Our team can provide vent pipe cleaning every three months.

If you are noticing your clothes are taking longer to dry than normal, or you would like to ensure your dryer vent is safe and clean, look to our competitive dryer vent cleaning in Fairfax County, VA. Contact our company today at 1 (888) 444-4712 to schedule your next appointment.

Issues of a Dirty Chimney

chimney sweep washington dcAt High’s Chimney Service, we believe your fireplace is a functional yet charming feature of your home. Like with many home features, it is critical to invest in regular maintenance and preservation plans to help protect the safety of your loved ones and your home. Below we discuss the possible issues that can be linked with a dirty chimney.

Chimney Fires

Harmful debris, such as soot and creosote can accumulate in your chimney over time, creating an ideal environment for a chimney fire due to their combustible characteristics. Chimney fires are dangerous because they can spread to other parts of your home.

Health Problems

Dirty chimneys can become clogged over time without a thorough chimney sweep in Washington, DC and the surrounding areas. When your chimney becomes clogged, it can cause a poisonous gas called carbon monoxide to build up in your home. Carbon monoxide can be harmful and deadly if inhaled, so it is vital to have regular chimney sweeps and inspections.

Smoke Damage

When your chimney becomes dirty and clogged with soot, it can also clog your flue and cause the smoke not to rise. If the smoke does not rise and exit your chimney, it can enter your home and create unwanted smoke damage to your belongings and your air.

Contact us today at 1 (888) 444-4712 to learn more about our chimney sweep services and to schedule an appointment.