Burglars love French doors they really do. Even inexperienced thieves know that a house with French doors is likely to allow them quick and easy access into the property. This is why they should be at the top of your burglary prevention checklist. French doors are popular with residents because they can make a beautiful addition to any home. Aside from looking nice, and often leading out onto a pleasant patio or deck area, they also let in lots of light. However, these types of doors can come at a cost if you’re not careful. They are perhaps the most vulnerable of all the doors when it comes to break-ins. Because most of them are out the back, that doesn’t mean they’re out of site. In fact, side and back doors are the favoured point of entry of most property crimes. Your main question now is how to secure my French doors.
The presenter in this video shows the best way to secure French doors from the inside.
French door security depends on your doors. They will all have their weaknesses, so you need to identify what yours are, and then look for ways to fix them.
There are a lot of glass panes in most French doors, and this makes them particularly vulnerable. However, a burglar isn’t going to be able to squeeze through the tiny aperture of a broken pane because it’s just too small. What they usually do is break a single pane of glass, reach in with their hand, unlock the doors and let themselves in. Therefore, your security on the inside is paramount as the presenter in the video above points out. He also shows how to strengthen the doors main weakness, which is the divide between the two doors.
Another problem with plain glass doors is that burglars can peer through them to see if anyone is home or not. The glass of most front doors, however, tends to be frosted, coloured, uneven (distorted) or all three, making it hard to see through.
Tip: For new doors, consider laminated glass or hurricane-rated glass as it’s incredibly tough and very difficult to break. 
Locks and Hinges
It sounds obvious, and it should be, yet so many people don’t change the weak and inadequate locks and hinges that come with these doors. Another big problem is short hinge screws. You want them to be at least 3-inches long. As for the deadbolts, make sure they have a minimum1-inch throw. Note too that mortise locks are usually a lot stronger than the standard bored type locks.
The best French door security will have a 3-point locking system. For doors that come as a pair, consider locking (securing) one of them permanently. This alone will make it a lot more difficult for a burglar to force the doors open.
Security bars are a simple yet effective measure you can take to prevent a wannabe burglar from kicking your doors in. You can even buy security bars that come with alarms.
If you haven’t purchased your French doors yet, think about the materials. In general, opt for thick wooden doors, the thicker the better. Consider hurricane-rated glass too. A steel frame will also add another layer to your French door security.