How to Fit and Install External French Doors

If you have just purchased some new French doors, then you are probably eager to fit them. Installing new French doors in an existing frame should be a simple job, as long as you have measured the doors correctly according to our guide to measuring and sizing French doors. If, however, you need to fit a new frame as well then you will need to install the frame into the rough opening first.

Before You Start

• Make sure that the door is the correct size, and measure the opening too. Do not remove your existing frame until you are certain that the new one will fit!
• Always follow the rules “measure twice, cut once”, and confirm the level and plumb carefully as you fit the frame.
• Because of the size of the doors, make sure that you have someone on hand to help you – don’t try to do the job alone!
• Try to choose a dry day to fit the door, and make sure you give yourself plenty of time to complete the job
• Paint the door before you hang it, and give the paint enough time to dry before disturbing it

Fitting the Doors

Expanding an existing opening is beyond the scope of this guide, since it may require disconnecting electrical wiring, and making alterations to structural walls. These are things that should only be attempted by someone who is knowledgeable and skilled in construction. Hanging a door in an existing frame, or even replacing a frame into an existing opening is a more modest task.

If you have had to enlarge the opening to fit your new French doors, then you will want to make sure that the wall in which the doors are to be placed is properly insulated. Remember that the vapour barrier for the insulation should face the interior of the property.  After insulating the wall, you can start work.

1. Lay the drywall sheet, and apply drywall mesh over any cracks. Smooth out the seams, and then leave them to dry.
2. Next, lay the sill plate, and apply caulk to ensure that the seal is weather-tight.
3. Set the new frame into place, and make sure that it is plumb. You can nail the frame in place with a single nail in each corner to begin with, and then use shims across the top and along each side to ensure that the frame fits properly and is level and plumb. Pay close attention here, because French door sets will highlight issues with a badly hung frame fare more clearly than a single door ever would. It will save you a lot of hassle in the future if you make sure that the frame is properly aligned now.
4. Once the frame is in place, you can hang the doors. This part is definitely a two-man job. Put the doors into the frame and secure the hinges. Open and close the doors several times as you go, to make sure that they move freely. Make sure that there is enough space at the bottom of the door for any flooring or carpet that you want to use. Adjust the hinges as necessary to ensure that the doors move freely and that they do not slam shut too quickly.
5. Once the door is in place, secure the frame in its final position, and add a second layer of drywall so that the wall is smooth and even. Add caulking and compound as required around the joints, and then install the door trim.
6. Make sure that all nail holes are spackled, and then paint the wall and the frame with the desired finish.
7. Fit any hardware/accessories (such as draught excluders / handles / door knockers / letterboxes) to the door.
8. Test the door again, fit doorstops to the inside wall, if required.

Security

External French doors should feature double glazing (not single glazing) and be fitted with a three point locking mechanism for security, not just a single lock. Depending on the type of door, you might also want an inner security screen. If you have a house alarm, consider fitting sensors to the door as well for added peace of mind. Remember that most burglaries are opportunistic, so if your doors appear secure, then that will help to put off any would-be intruders.

For the back door, having top and bottom key operated 5 lever mortise locks is usually sufficient. For front doors, which tend to be more exposed, you may want surface-mounted locking bolts which are fitted to the frame at a 90 degree angle to the grain of the wood – this will make sure that the door frame is highly unlikely to split should someone put pressure on the door. It is not uncommon for French doors to open outwards, and if you opt for this, then use hinge bolts as well.

Fitting French doors is a relatively simple job, but it is important to remember that external doors are more than just entry/exit points – they are also an important security feature for your home. For this reason, you should make sure that you have the time to do a good job, and that you are confident that you know what you are doing. If you have any doubts at all, consult an expert. It is better to pay to have the job done well the first time around, than to be faced with great inconvenience and an expensive bill for remedial work at a later date!

Common Issues

Whether you're fitting an external French door as a front or back door, you'll need to make sure the fit is just right. If you have a door opening that is slightly smaller than a standard size, then you can usually adjust wooden doors to fit. Our external timber doors have generous lippings which can be sanded/planed to make a bigger door fit a smaller opening. Try to remove an equal amount from both doors, and remove some from both sides of the door to create a smooth fit. If you do have to adjust a door in this way before you hang it, then let the door sit in a dry place overnight after trimming it, before hanging it. This will reduce the likelihood of the door twisting, bowing or drooping.

Some Final Tips

If you have any questions about our range of external doors, or are concerned about fitting/installation, then please do not hesitate to get in touch with us. We would be happy to answer any questions that you might have, and to work with you to find the best possible doors for your needs.