Recently we told you about filling the gaps around the picture rail in our bedroom with caulk and redoing the seal around our bath with silicone. There is a huge selection of different sealants available and choosing the right one can be difficult.

Hopefully, our quick guide will make choosing the right product a bit easier.
Basically, both acrylic caulk and silicone do the same job but there are some significant differences to take into account when choosing whether silicon or caulk is right for your application.
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Silicone

Pros of silicone:
- Silicone is highly elastic and will adhere well to any smooth surface
- Because of its elasticity, any movement in the joint should be tolerated and the silicone won’t tear. That’s why it’s better than acrylic caulk for larger joints.
- Silicone is ideal for rooms with higher moisture levels (like kitchens and bathrooms) as it is water-resistant
- It’s ideal for sealing around baths, showers and other sanitary ware
- It’s cold and heat resistant as well as non-yellowing
- Silicone is vailable in different colours, including clear
- In bathrooms only use sanitary silicone, which contains a fungicide to prevent mould
Cons of silicone:
- You can’t paint over silicone
- When it’s dry, you can’t apply another layer on top
If you are using silicone for your project, don’t forget to check out this guide on how to apply sillicone.
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Acrylic Caulk

Pros of caulk:
- Caulk dries quicker than silicone
- It’s less tolerant to movement than silicone – should only be used in areas where there is little or no movement
- Caulk is ideal for filling gaps in living areas like between skirting boards, picture rails and built-in furniture
- You can paint over it with any paints or varnishes
- While it’s still wet, it can be easily removed with a damp cloth
- When completely dry, acrylic caulk is much harder than silicone
Cons of caulk:
- Acrylic caulk tends to shrink slightly when drying, so the application of a second layer may be necessary
- It’s not for use when in contact with water (i.e. around sanitary ware)
It depends on what you want to do and where you are planning to seal, but as always check the manufacturer’s instructions and check the suitability for your project and any guidelines.
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If you are using caulk for your project, don’t forget to check out this post where we share how to achieve perfectly smooth and clean caulk.
We hope this caulk vs silicone guide makes it easier for you to choose the right product for your next project.
Dcam says
Apologies this is such an old post but I’ve found it so helpful – thank you! Where small cracks/gaps have formed between the skirting board and wall, would you use caulk or wood filler? Many thanks!
Christine says
Always happy to help! Around staircases is always one of the most difficult areas to fill cracks as there’s a lot of movement. If the gaps aren’t too large, use caulk but make sure to use one that’s super flexible and tolerates movement. Something like this one would be ideal https://www.toolstation.com/toupret-fibacryl-flexible-filler/p40082.
Hope that helps!
Cx
Gerry says
Another pro tip they don’t tell you: caulk is for fillings gaps less than 2mm. For larger gaps use filler (because it doesn’t shrink and you can sand it).
Christine says
Totally agree with you, Gerry! Thanks for sharing. People often think that they can fill anything with caulk but it can quickly become messy.
Cx