How Much Can You Cut Off An Exterior Door?

While exterior doors are produced with standard sizes, sometimes you need a smaller fit for your door frame. You can have it customized on the lumber yard, but you can also do it yourself. However, the question is this: how much can you cut off an exterior door?

Take note that you must plan the woodwork project before reaching for your saw. You have to consider several factors, including the type of door you have as well as the materials used in it.

In this post, I will discuss how much you can cut from your exterior door and how to do it properly.

How much longer can I cut from an exterior door?

The answer to this depends on the type of door you have. Most exterior doors are either solid core or solid wood.

Exterior doors have a standard length of 80 inches. However, old houses tend to have thicker thresholds. This will require you to trim the bottom of the new door you’re planning to install.

For solid core doors, most manufacturers allow up to 3 mm to 5 mm on each side. However, some of these doors have wider outer frames that will give you more allowance for trimming.

Meanwhile, solid wood doors can be trimmed even further since it doesn’t have a pressure-treated inner material. Still, you should follow manufacturer suggestions to prevent ruining the overall design of the door.

On the other hand, non-fire-rated and fire-rated doors are usually suitable for cutting at any size. This is the case as long as they are made of one solid and unfinished material. It has no panels or molding, so it’s not the most stylish pick. But if you’re willing to do the finishing, this door type will surely you well.

Take note that trimming a door is more than just cutting wood. You have to be careful because going beyond the recommended trimming tolerance can reduce the door’s lifespan.

Remember that exterior doors are more exposed to outdoor elements. When trimmed haphazardly, it will expose the door material to rot and premature damages.

If you have an expensive door to trim, I highly suggest letting a professional do it for you. You should consider this, especially if you don’t have experience with woodworking.

Another option you have is a custom-made door. This will be sized based on the door frame that you have, so you no longer have to do handyman work just to get the right fit.

Tips in trimming an exterior door

It’s important to plan before trimming your exterior door to prevent irreversible damages. Unlike hollow core interior doors, exterior ones are more expensive. You can’t afford to ruin it with poor trimming.

To help you out, you should keep the following tips in mind:

  • Mark before trimming. It’s crucial to mark the trimming spot before you plug your circular saw. Next, you should score the veneer to make a guide where the saw blade will pass through. Next, you should tape the upper option to prevent ruining the veneer on that area.
  • Use a straight edge. Once you’re ready to trim the door, you should place a straight plank right beside the saw. This will prevent the blade from getting out of line and ruining the trim.
  • Get the right blade. For trimming exterior doors, you should use a sharp saw blade with at least 18 teeth. This will give you a smooth edge after the trimming is done.
  • Avoid splinters. One of the things you need to avoid when trimming an exterior wood is splintering the wood or splitting the edges. This is why you should always use a sharp circular saw. But for cuts smaller than 3/16 of an inch, it’s best to use a power planer instead.
  • Take measurements first. It’s easy to over-trim a door if you’re not taking measurements. Before you make the first cut, you should measure your intended length and how much you need to remove. The last thing you want is an exterior door too short.

How much does it cost to trim down a door?

Most contractors will charge the trim per door, though they can give you a package deal if you have multiple doors to trim. On average, it will cost you $100, but it could be as much as $300, depending on the material.

As much as possible, avoid carpenters that charge by the hour as this system can be abused easily. Instead, look for an experienced carpenter who can give you a fixed price per door.

Can you cut two inches off a door?

For solid wood doors, cutting up to two inches may not be a problem. Removing such length might be necessary if you have thick carpeting or smaller than usual door frames.

However, if you have a hollow core or solid core exterior doors, you don’t have the luxury of length to trim. Removing two inches will expose the inner material of the door.

For hollow core types, cutting a two-inch length will make your door less solid. Also, you’ll need to do more work to seal the part you trimmed to prevent moisture from entering.

How much can I cut off the side of a hollow core door?

Most hollow core doors can be trimmed up to 5 mm per side. However, some manufacturers like LPD only allow 3 mm per side when it comes to trimming.

Despite being an interior door, you should still observe proper technique when trimming hollow core doors.

Can I trim a door without taking it off the frame?

It’s challenging and sometimes impossible to trim a door without removing it from the frame. This is true for exterior doors made of solid wood or solid core material.

To trim these door types, you need to measure, mark, and use a circular saw. You can only use this tool if the door is removed from the side jamb.

But if it’s impossible to remove the door, you can use an oscillating tool. This will remove the excess length, but the result isn’t as smooth as you’d want it to be.

However, you have to keep in mind that trimming a door while hung will make it impossible to polish the bottom. Also, it will be too much to put back the weatherstripping underneath.

Take note that you should never trim a solid core exterior door while hung. You need to reblock this door after trimming, which isn’t possible if it’s still attached to the door frame.

Can you trim an MDF door?

MDF or medium-density fiberboard doors are cheaper alternatives to the solid core and solid wood exterior doors. You can still trim this, but you should do so at the bottom. The bottom frame of MDF doors is stronger and won’t splinter easily.

Also, each manufacturer will set a trimming tolerance, which can range from ¼ to a whole inch. However, if you need to cut further, you can remove the outer frame, cut the length, and re-glue the frame back. This way, the inner material won’t be exposed.

Conclusion

How much can you cut off an exterior door? Each manufacturer has its recommended trimming tolerance. It can range from 3 mm to 5 mm, though there’s always a workaround to trim more length. Make sure that you use the right tools and measurements for the best results.

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