Internal Doors with 32mm Trim Allowance

If you live in an older property, have sloping floors, or you’re replacing frames during a renovation, finding internal doors with enough trim allowance can be a bit of a minefield. Plane off too much and you risk exposing the core or, in the case of fire doors, invalidating the certification.

In this guide we’ll walk through what a 32mm trim allowance actually means, when you might need it, and how our Deanta and LPD internal door ranges can help.

What does a 32mm trim allowance mean?

When we talk about “internal doors with 32mm trim allowance”, we’re talking about how much material can safely be removed from the edges of the door on site while still keeping it structurally sound and within the manufacturer’s guidelines.

Typical reasons you might need a larger trimming allowance include:

• Uneven or sloping floors

• Older properties where openings aren’t perfectly square

• Replacing thicker carpets with hard flooring

• Adjusting doors to fit existing or slightly altered frames

A generous trim allowance gives your joiner more flexibility to scribe the door neatly to your opening without compromising the look or performance of the door.

Deanta internal doors – up to 32mm trim on standard doors

If you’re specifically searching for internal doors with up to 32mm trim allowance, our Deanta range is one of the most flexible options.

• Standard Deanta doors – trimmable by up to 32mm in total (typically across the height and width, as per Deanta’s fitting instructions).

• Deanta fire doors – trimmable by up to 30mm in total, giving excellent flexibility while still maintaining fire performance when installed correctly.

This extra allowance is ideal when you’re working with:

• Renovation projects where openings vary slightly room to room

• Older homes with original, “characterful” frames

• Properties where floors have been levelled or changed over time

You can browse the full Deanta collection here:
👉 Deanta doors at Doorphoria – https://doorphoria.co.uk/brand/deanta/

Each product page will show the relevant technical details, but if you’re unsure, just drop us a message and we can double-check the trimming guidance for the exact model you’re buying.

LPD internal doors – generous 20mm lippings for on-site adjustment

Our LPD internal doors also offer good flexibility thanks to their 20mm lippings on many designs. These larger lippings are designed to allow for on-site adjustments while keeping a neat, finished edge once the door has been trimmed and painted.

In practice, this means many LPD doors can be trimmed to suit slightly awkward openings, while still looking like a factory-finished, made-to-measure door once hung.

You can explore the range here:
👉 LPD doors at Doorphoria – https://doorphoria.co.uk/brand/leeds-plywood-doors/

As with any manufacturer, exact trimming allowances can vary between models, so it’s always worth checking the fitting instructions or asking us to confirm for a particular door if you’re planning a larger adjustment.

Important exception – our industrial / urban crittall-style black doors

The above trim allowances apply to most of our Deanta and LPD ranges. However, there is an important exception:

Our new industrial / urban crittall-inspired black internal doors are designed with slimmer stiles and rails to achieve that refined, glazed-screen look. Because of these thinner sections, they can only be trimmed by around 3mm in total.

That means:

• They’re best suited to standard, fairly true openings.

• They shouldn’t be used where a large amount of material needs to be removed.

• If you know you’ll need to take more off to make a door fit, it’s safer to look at a Deanta or LPD design with larger lippings instead.

If you’re drawn to the industrial look but have awkward openings, let us know your sizes and we can advise whether these crittall-style doors are suitable, or suggest a more trimmable alternative that will still complement that aesthetic.

Standard doors vs fire doors – why trim limits matter

It’s especially important to stick to the stated trim allowance on fire doors:

• The fire rating (e.g. FD30) is tested and certified to very specific dimensions.

• Removing too much material – especially from the top or bottom – can affect how the door performs in a fire.

• For Deanta fire doors, the 30mm trim allowance offers more flexibility than many other brands, but it’s still essential your joiner follows the official guidance and uses the correct intumescent strips, ironmongery and frame setup.

If you’re unsure whether your opening can be safely accommodated within the trim limits of a fire door, it’s always best to check with your joiner and with us before ordering.

How to choose the right door for an awkward opening

If you know your openings are a bit tricky, here’s a simple approach:

1. Measure the opening carefully

   • Measure width and height at three points (top, middle, bottom).

   • Note the smallest measurement – that’s your working size.

2. Check the door size closest to your opening

   • Compare your opening to standard door sizes.

   • Work out roughly how much material needs to come off each edge.

3. Match to a suitable trim allowance

   • If you need more flexibility, look at Deanta doors with up to 32mm (standard) and 30mm (fire) trimming.

   • If your adjustments are more modest but you still need some room to work, consider LPD doors with 20mm lippings.

   • Avoid heavy trimming on our industrial / urban crittall-style black doors, which allow for only around 3mm of adjustment.

4. Ask if you’re unsure

   • Email us your measurements and the door you’re looking at and we can advise whether it’s within the manufacturer’s guidelines.

Working with your joiner

The best results come when you, your joiner and the product spec are all aligned:

• Share the manufacturer’s fitting instructions with your joiner before installation.

• Confirm how much trimming is needed and that it sits comfortably within the stated allowance.

• On fire doors, make sure your installer is familiar with fire door installation requirements, ironmongery and seals.

A good joiner will appreciate having a door with generous lippings – it makes their life easier and gives you a cleaner finish.

When a made-to-measure door might be better

Even with generous trimming, there are some situations where it’s better to look at a made-to-measure solution or have a joiner make a bespoke door:

• Very small or unusually tall openings

• Period properties with heavily out-of-square frames

• Situations where trimming would exceed the 32mm / 30mm / 20mm / 3mm guidance

If that’s the case, we can still help you choose a style and specification that suits your project, then your joiner or door specialist can work from there.

Need help choosing an internal door with the right trimming allowance?

If you’re trying to work out which Deanta or LPD internal doors will suit your opening – especially if you need up to 32mm of trimming – we’re always happy to help.

Send us:

• Your rough opening sizes

• Whether you need standard or fire doors

• Any particular style you have in mind

…and we can point you towards the most suitable options from our Deanta and LPD ranges, or advise when our industrial crittall-style doors (with only 3mm trim allowance) will work in your space.