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Trimming your doors to size

jb kind trent oak internal fire door pre finished 2

Many of our customers ask if a door can be trimmed. The answer solely depends on the door design. Different manufacturers have different trimming limits on their range of doors. If you plan to trim a door, we recommend consulting with a carpenter to avoid any mistakes.

Trimming Internal Doors

When it comes to trimming internal doors, most door manufacturers offer various trimming limits (usually 3mm from each side) and advise not to go over them. This does vary depending on the manufacturer. At Internal Doors UK, many of our doors allow for 6mm to be trimmed from each side. If you need to trim more than this, contact our experienced team to see if this is possible. It is important to note that trimming over the limit could void the warranty.

The door’s construction will affect how much can be trimmed—trimming more than the required amount could compromise the design. If your door has a hollow core, you could cut into the void, resulting in the door being unusable. 

Trimming your doors to size 1
Trimming your doors to size 3

Trimming External Doors

The amount that can be trimmed from External Doors also depends on the manufacturer. Our Xl range can be trimmed up to 10mm on each side, and our LPD range varies from 3-5mm on each side. Feel free to call us on 02077706506 to discuss your requirements or email us at If you decide to trim your external doors, the edges will need to be finished to ensure the door remains waterproof and does not break the warranty.

Trimming Fire Doors 

When it comes to fire doors, we recommend not trimming these at all. Doors are strictly tested to their precise dimensions with smoke seals and any required hardware. Trimming a fire door could mean that it no longer provides 30 minutes of fire protection. If you require fire doors as a legal requirement, you could break the law by installing fire doors that do not meet those requirements. 

Fire door blanks are a great choice if you need to trim doors to fit. These are pieces of wood with no design and can be cut to size needed. Fire door blanks are a cheaper option but will still need fire rated seals. 

Alternatives to trimming doors

Door blanks are designed to be cut to the size you require. There is no design on these doors, but they could be a great option if your home has non-standard size doorways. Another option is to opt for your made to measure service, this will allow you to choose the exact sizes you need, and we can have them specially made. Visit our made to measure page for more details. 

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