The L marking on a door closer stands for latch speed and the S marking stands for swing speed. These two letters inform what part of the door closer you may be adjusting. The latch speed being the short final swing the door makes before closing and the swing speed being the long swing of the door when closing.

While not strictly required, it is highly recommended to shim both sides of a door. Shimming both sides allows you to make minor adjustments for wall framing that isn't perfectly plumb, ensuring the door is level and hangs evenly. This practice helps the door swing open and close smoothly, reduces the chances of the frame warping, and can be used to center the door within the wall opening. If you are working alone, you may find it easier to remove the door slab to lighten the weight while supporting the frame and inserting the shims. With two people, the process is generally faster and easier, whether the slab is left in place or not.

High-tech solutions and strategic placement can help ensure the safety of your pet door. Pet doors can pose security risks, as well as the risk of stray or wild animals entering your home, but modern pet doors offer options like collar-based sensors to ensure doors will only open for your pet, and installing a pet door in an out-of-sight location or in a wall rather than a door can help to avoid intruders using the door to gain access to your home.

Yes, barn doors can be too heavy, although the limitation is usually imposed by the mounting hardware you buy and not your home’s framing, unless you’re building an unusually wide door. To keep the weight down, you can opt for 1-by material rather than 2-by material, and choose a softwood like pine rather than a hardwood like maple or oak. Check the weight limits on your mounting hardware, and always attach your door track to studs rather than to drywall anchors.