How To Fills Gaps With Caulk

One of my favourite products used on a daily basis, caulk. Maybe you have never used caulk to fill gaps or smooth out uneven surfaces. Trust me when I say, it’s amazing. Today I’ll explain how to fill gaps with caulk to achieve a professional finish.

What Is Caulk

Caulk is a flexible filler/ sealant used to fill gaps and seal joints. Generally used in building work, PVC installation and decorating. All caulks and sealants come in tubes that are used in conjunction with a Caulking Gun, which dispenses the caulk. Popular sizes of caulking tubes are 290ml and 310ml, both sizes are compatible with most caulking guns.

For the purposes of filling gaps with caulk, I am going to refer mostly to using decorators caulk. The principles and techniques I explain will transfer over when using other silicone or sealant based products.

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How To Fill Gaps With Caulk

1) Before you start to use your caulk, cut the tip (nozzle) at a slight angle. When dispensing the caulk you will naturally hold the gun at an angle. By holding the gun at a similar angle to the nozzle assists with flow and even distribution of caulk across the surface.

How To Fill Gaps With Caulk

2) Ensure that the surface your filling is free from dust and dirt. Remove any loose paint or debre with sandpaper prior to caulking the gap.

3) Load the caulking tube into your caulking gun by pulling back the plunger arm. Press the trigger until the caulk starts to come out of the nozzle. Press the trigger release lever to stop the caulk flowing, your gun is now primed ready for use.

4) Place the tip of the nozzle against the surface next to the gap you wish to fill. Press the trigger, as the caulk dispenses move the caulking gun in a smooth, flowing action across the surface. The goal is to distribute an even bead of caulk across the gap.

5) The final step is to smooth the caulk, dampen the tip of your finger and run it across the bead of caulk. This helps to push the caulk into the gap and distribute the caulk evenly across the gap.

Tip: Use a damp cloth to wipe off any surplus caulk left on the surface.

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How To Fill Big Gaps With Caulk

In most cases fine cracks and gaps can be filled in one go with caulk, but what about big gaps.

The process of filling large gaps with caulk is pretty much the same with two exceptions. When filling a large gap, don’t point the nozzle directly into the gap, instead build up several layers.

Place the first bead of caulk onto one surface (edge of skirting board), then place another layer on top of the first bead until the gap is covered.

Use your finger to smooth and leave until dry. Most caulks will shrink when dry, meaning that you will need to fill the gap again to successfully hide the gap.

Another method of filling large gaps is to use Expanding Spray Foam. Once the spray foam is dry, trim off the excess leaving the spray foam slight shy from the surface. Caulk the remaining gap as normal, the expanding foam will stop the caulk from falling into the gap.

Caulk’s gap filling properties have their limitations. Gaps above 10mm will be difficult to fill with caulk alone.

I use caulk on daily basis to fill the gaps between the skirting boards and wall, around door frames, edges of ceilings and any joinery that is to be painted.

Flexible Gap Filler

Most caulks today are flexible which is favourable when filling gaps. Wooden substrates expand and contract with changes in temperature and humidity. Flexible gap fillers move and flex with the substrate, thus avoiding cracking.

Flexible caulk is cheap, waterproof and can be painted once dry.

Tip: Prime newly caulked areas to avoid cracking, especially when painting with emulsion paint. I use Zinsser Bullseye 123 Primer as my go to primer.

If your painting with a latex or oil based paint, you don’t need to prime the caulk first.

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Caulking Tips

1) Keep a damp cloth or paper towel handy for keeping the nozzle clean

2) Hold the caulking gun at the same angle when moving the gun

3) Cut a small angle on the nozzle for fine cracks and small gaps. Trim a larger angle at the nozzle for bigger gaps.

4) Large gaps will need to be caulked again once the first fill is dry

5) Purchase a caulking gun with a non drip feature, (Newborn 930 GTD). This will keep the nozzle clean and free from excess caulk when the trigger is released.

6) Use decorators caulk to smooth out uneven surfaces, for example where the ceiling meets the wall.

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