Decorators Caulk or Polyfilla?

by Sam Wood | Last Updated: 16/07/2021

So you have a crack to fill, or maybe a gap in your skirting board that needs to go. Do you need to use decorators caulk or Polyfilla? (for ease we are using Polyfilla as our example but any similar filling product works the same). Well, each of these products has completely different properties and use cases, so to get the best results you need to use the correct one. I have gathered together all the info for you below on when and how to use each product and together with my own knowledge from being a tradesman I have compiled this complete guide, so read on to learn more.

Decorators Caulk or Polyfilla?

Let me answer this quickly for you. If you are filling walls/plaster/brick then you want to use Polyfilla. If you are filling skirting board gaps/architrave etc then you will want to use decorators caulk. That is the base outline but let me break down why you want to use one or the other.

Polyfilla \ General Fillers

Polyfilla or any general filler for that matter are great at filling cracks in walls and plaster. These fillers are designed to not shrink or crack once applied, although you do seem to get a little shrinkage, but this is easily cured by a little top up layer of filler.

Cracks in wall filled with filler

Cracks in the  wall filled with filler

These fillers come either in a ready-mixed or powder form and are really easy to apply.

What makes Polyfilla different to decorators caulk is that it is sandable and drillable. This is what makes it the preferred choice for filling walls. You can apply the filler then sand it down to get a perfect finish.

Decorators Caulk

This is the stuff that comes in tubes and is applied using a caulking gun. You want to use decorators caulk on the tops of skirting boards and things like door architraves.

Decorators caulk is more flexible than filler so will not crack in areas where you will get a little movement. It does tend to suffer from shrinkage and cannot be sanded, that’s why you don’t want to use it on walls.

Decorators Caulk

Decorators Caulk

In another article on this site which you can find here, I showed how to use decorators caulk to fill gaps in a skirting board corner. This is the kind of job that caulk is suited to.

I don’t want to repeat that article here but I will include a few photos to show you how you can use decorators caulk.

Caulk Applied To The Entire Gap

Caulk Applied To The Entire Gap

First, you apply the caulk to the gap.

Push The Caulk Into The Gap Using Your Finger

Push The Caulk Into The Gap Using Your Finger

Then push it into the gap using your finger.

The Gap All Caulked Up

The Gap All Caulked Up

An voila, you are done!

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Wood by name, wood by nature. I am a fully qualified, time-served, award-winning joiner with an NVQ Level 3 in Carpentry and Joinery as well as an HNC in Construction. Beyond my joinery qualifications, I have also earned a degree in building surveying. I believe these qualifications make me perfectly positioned to provide expert advice on many different areas of DIY as well as share all of the tips I have picked up in over a decade working on building sites!