How do you fix a gap between concrete steps and a house?

Key Points:
✅ Urethane caulk is the best material for filling the gap between concrete steps and a house.
✅ Before applying urethane caulk, clean the gap, apply a primer, and measure the gap for accuracy.
✅ When applying urethane caulk, use a continuous zigzag motion, and finish by smoothing out any rough spots.
✅ Seal the urethane caulk with a low-shrinking caulk that is paintable and waterproof.
✅ Use painter’s tape and elastomeric sealant to finish the repair.

Hello! I’m Emily, a 23-year-old DIY enthusiast, who has worked on a number of projects over the years. I have been honing my skills in DIY and have learned a lot about repairing gaps between concrete steps and homes. In this article, I’ll take you through the process of filling the gap with urethane caulk.

Steps Description
Identifying the Gap Determine what caused the gap.
Measuring the Gap Measure from one side of the gap to the other.
Assessing the Damage Evaluate if soil erosion has caused the gap.
Preparing for Repair Clean the gap and apply a primer.
Choosing a Filler Urethane caulk is the best material.
Applying Urethane Caulk Cut the nozzle, insert a tube of urethane caulk, and apply in a zigzag motion.
Sealing the Caulk Choose the right type of caulk and seal around windows and doors.
Finishing Touches Mask off areas and smooth out any excess caulk.


If you want to fill the gap and make sure that it’s sealed properly, there are a few options available.

To help compare the different products, I have included a comparison table below.

But in my experience, one of the best ways to fix this gap is by using urethane caulk, which provides excellent adhesion and flexibility so it won’t crack or break away over time.

In this article, I’ll take you through the process for filling the gap with urethane caulk.

Identifying the Gap

Measuring the Gap

Once you’ve identified the gap between your concrete steps and the house, it’s important to measure it carefully. This will help you decide on the best way of filling it.

You will want to measure from one side of the gap to the other.

Depending on the type of caulk you use, and how much coverage is needed, these measurements can vary.

If possible, take two measurements for accuracy – one at the top of the gap and one at the bottom.

These measurements should be as precise as possible so that you know exactly how much urethane caulk or sealant is required to fill in your gap size accurately.

Knowing this before starting work makes tasks such as caulking or sealing much easier and far more efficient – ultimately saving time and money.

Assessing the Damage

The first thing you need to do when assessing how best to fix a gap between the concrete steps and your house is to determine what caused the gap.

In most cases, it is likely due to soil shifting beneath or around the steps, which can cause them to settle improperly or move out of alignment with the house.

In cases where there is soil erosion, it may be necessary to repair the area by adding more topsoil and then adding some form of reinforcement such as a concrete retaining wall or even concrete pavers in order to keep the area stable in the future.

If necessary, you can use a rotary tiller as well as sandbags or other soil-stabilizing materials for additional protection against future erosion.

In cases where natural settling has caused the gap, you may be able to adjust any ground around that area by adding or removing material from that side until it’s level with both sides of the stairs or at least close enough so that there’s minimal effect from use over time.

Depending on how large and deep this gap might be, other options could include:

  • Filling any voids with sand before resetting and anchoring them with metal stakes in order to provide better support over time.

It’s important to note that whatever form of repairs are performed should not result in changes that stress either your home’s foundation or walls beyond what they are normally meant to handle.

As such, heeding local building codes is advisable so as not to create any further instability overall.

Preparing for Repair

Cleaning the Gap

Before you can fill the gap between concrete steps and your house, it is important to clean out all dirt and debris.

To do this, I recommend using a putty knife and brush to thoroughly scrape the gap.

It is especially important to get any dirt lodged in the crevices of the concrete stairs for a successful repair job.

If desired, you can use a vacuum cleaner or compressed air to further clear the area.

Taking these precautions will help ensure that there are no hindrances when it comes time to fill the gap with urethane caulk.

Applying Primer

Applying a primer is an important step in repairing any gap between concrete steps and a house.

A quality primer creates a bond between the substrate and the product you will use to fill the gap.

When applied correctly, it will reduce surface tension and ensure better adhesion, which can help ensure that the repair job lasts longer.

I recommend using a water-based urethane primer when filling gaps between concrete steps and a house.

This type of primer is generally less hazardous than solvent-based primers, so it is safer to use around people and pets.

It also dries quickly and can be used on most types of surfaces, such as wood, concrete, masonry, or metal.

To apply the primer to your substrate, you will need some basic tools such as:

  • Drop cloths or newspapers for protection from any splashes or spills that may occur;
  • Paint brushes or rollers for wider areas;
  • Stirring sticks;
  • Rags;
  • Paint buckets;
  • Paper towels;
  • Goggles for safety;
  • Respiratory equipment for ventilation during application (if needed);
  • Caulking gun with spout adapter (to help apply even pressure);
  • Caulk remover (if necessary);
  • Rubber gloves (for hand protection).

Once you have all of your materials gathered together, plan on spending approximately 30 minutes applying the primer evenly across the substrate according to manufacturer instructions.

Once you have finished applying your primer to the substrate surfaces, you are ready to move on to filling any gaps between concrete steps and a house with urethane caulk – which will be covered in our next heading!

Repairing the Gap

Choosing a Filler

There are several options for narrowing this gap, so it is important to know what material to use for the job.

The best material for filling a gap between concrete steps and a house is urethane caulk.

This sealant forms an airtight bond with the concrete that won’t allow water damage, and it can withstand extreme climates.

It also won’t crack or separate due to temperature changes over time.

Other materials you may consider are polyurethane foam or slim-set mortar mix.

It’s best to look at both options to make an informed decision.

Below is a comparison table that outlines the differences between urethane caulk and polyurethane foam as filler materials:

Filler Material Urethane Caulk Polyurethane Foam
Advantages Forms an airtight bond with concrete; non-cracking; weatherproof; easy application Moldable design allows for multiple applications; insulates against heat loss; expands well in gaps from 1/4 inch – 8 inches wide
Disadvantages Takes time to apply properly; more expensive than other fillers Expands quickly while curing (may require frequent readjustment); contains VOCs that could be harmful if not used properly.

Using this table may help you determine which filler material will work best for your particular project and needs in repairing the gap between your concrete steps and house!

Applying Urethane Caulk

Applying urethane caulk is an effective way to repair the gap between windows, trim, and external surfaces.

Urethane caulk is a long-lasting caulking material that will not crack after expanding or shrinking due to temperature changes.

Here are some steps on how to apply urethane caulk for effective gap repair:

  1. Preparation: Thoroughly clean the gap by wiping it with a damp cloth and allowing it to dry completely. Apply an even bead of painter’s tape along the edges of the gap to create a smooth surface for the urethane caulk application.
  2. Applying Caulk: Cut the nozzle of an applicator gun into a v-shaped opening that is slightly bigger than the average width of your gap, then insert a tube of urethane caulk into the gun. Make sure you apply in a continuous zigzag motion, filling any cracks and crevices between surfaces until they are uniform with each other.
  3. Finishing: Carefully remove any excess material from around your newly filled area using a damp cloth or soft bristle brush, then smooth over any rough spots with fine sandpaper or steel wool once it has dried completely. Finally, remove excess dust from sanding and apply paintable caulking compound if necessary for protection against future wear and tear caused by weather conditions or other environmental factors.

Finishing the Repair

Sealing the Caulk

Sealing the caulk is an important step in finishing an effective repair.

Choosing the right type of caulk is essential because it can affect the strength and longevity of your repair.

In general, you should select a type of caulk specifically formulated for the material you plan to seal, such as wood, plastic, ceramic, or metal. In addition to choosing the right type of caulk, there are several other steps that should be taken when sealing with caulk:

  • Use low-shrinking caulks that are paintable and waterproof to ensure a strong seal.
  • Trim off any remaining bead after smoothing it down with a damp cloth. This will prevent cracking problems from occurring down the line.
  • Make sure to wait for each layer of caulk to dry before applying another layer if multiple layers are needed (for instance if applying silicone).
  • Seal around windows and doors before painting for longer lasting results.
  • Be sure to clean up excess or drips promptly as some caulks cannot be painted over once dried.

These tips can help ensure a solid seal for your repair project when sealing with caulk so that you don’t have to worry about water getting in or air escaping from your interior space.

Finishing Touches

Once the gap between the steps and the house has been filled with urethane caulk, there are a few things that need to be done to finish the repair.

First, it is important to mask off any areas you don’t want to be exposed.

This can be done by using painter’s tape along the edges of the steps and house.

Next, use a putty knife or spatula to smooth out any excess caulk that may have been applied before it cures.

Finally, remove any tape you used for masking and smooth out any edges or corners with sandpaper.

You might find that after filling in the gap with caulk, there is space still visible between the steps and house despite your best efforts.

It might help to fill this remaining space with an elastomeric sealant or a foam insulation board that can be cut down to fit tightly in place before being covered with urethane caulk.

Doing so will provide extra protection against drafts and moisture infiltrating your home’s interior spaces by forming an additional layer of insulation and moisture barrier between them.

In addition, if you’re looking for a way to prevent future damage from occurring due to expansion and contraction of concrete slabs around your home due to temperature changes, consider using expansion joint inserts that are available at most hardware stores and online retailers.

These will help absorb pressure from different elements such as expanding soils or ice buildup on winter months that can cause gaps between concrete steps and your home.

For added security, some products even come with self-adhesive backing for easy installation with minimal effort – no mess required!


After thoroughly researching the best methods of filling a gap between concrete steps and a house, my conclusion is that urethane caulk is the most effective solution.

Urethane caulk stands out as an excellent option due to its water resistance and ability to expand and contract with temperature fluctuations.

It has a long lifespan, bonds well with concrete, and is easy to apply. In summary, urethane caulk is an excellent choice for this type of task.







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