Two main reasons doors and windows are poor sound isolators are poor seals and lack of mass. To improve sound isolation: 1. Check doors and windows for issues like thin materials, hollow cores, or single pane glass. Ensure tight seals around frames and sweeps at bottoms. 2. Replace or add seals where needed and use dense, flexible materials. Adjust or install sweep seals at bottoms of doors. 3. Consider solutions like solid core doors, double door assemblies, adding a second pane of glass to windows, or creating an airlock with communicating doors.

2. DOORS AND WINDOWS
Whether residential or commercial, most doors are poor
isolators of airborne sound.
Two main reasons for the poor performance are;
1 poor seals and
2 lack of mass in the door itself.

3. DOOR AND WINDOW CHECKPOINTS
• Check the basic structure for problems —
Are your doors too thin?
Are they hollow?
Do your doors have louver panels?
Are windows constructed with a single pane of glass?
How thick is the glass?
• Check tightness —
Are door and window jambs without seals or gaskets, or are the gaskets worn out, torn
away or out of alignment?
Check seals by closing the door or window on a piece of paper. If the paper is easily
pulled through the jamb, and you feel little or no resistance, your seals are not as good
as they should be. Anywhere you can feel air movement or see light shine through is
also a trouble spot.
• Check the sweep-seal at bottom of door —
Does the door bottom seal tightly over threshold?
Again, the paper test works well.

5. DOOR AND WINDOW SOLUTIONS
-Doors need to be as heavy as possible and airtight. A double-door assembly
will always out-perform a single door.
The door, or more accurately the door slab, is often hollow. Fortunately, most
hollow core doors can be exactly replaced with solid core doors. The
difference in mass, yields significant improvements. You will be faced with
different slab core options such as particleboard filled, MDF filled or a mineral
core. It is better to stick with either particleboard or MDF, since mineral core is
more expensive. Now this heavy doors needs to be sealed.. Standard door
weather strip works well for the top and two sides of the door, but that big gap
on the bottom of the door is too big for lightweight, thin weather strip.
Consider installing a block to the underside of the door, then sealing with a
door sweep.

7. • If your doors and windows do not have seals, or they are torn or missing,
add new seals. Magnetic seals work the best but, if they are not an option,
make sure to choose a dense, flexible material like neoprene. When the
door or window is shut, the seals should be in line with, and compress
against, a flat clean surface. The goal should be an air tight connection.

8. • Many doors will have a drop-down sweep seal that seals against the threshold when
the door is shut. Often these are simply out of alignment and can be adjusted with a
screwdriver. If there is no sweep seal, have one installed. Typically they consist of a
sweep-seal closure and threshold plate. They will require frequent checking to ensure
proper alignment.

9. Most rooms it's possible to fit doors to either side of the wall, leaving an air gap
the thickness of the walls between them. Both doors should be fitted with seals,
but only one needs to have a pressure latch -- the outer door can have a spring
closer
. It's also vital to make the door airtight, so use heavy-duty seals around the edges,
not forgetting the threshold below the door. If you can afford it, fit a compression latch
(similar to those fitted to industrial freezers), so that the door is squeezed more tightly
shut as you pull the handle down. These are mechanically simple latches that work
by running up a tapered plastic wedge screwed to the door frame, so that the door is
forced harder against the seal as the handle is closed.
• Louvers in a door can simply be taken out and the remaining hole insulated and
surfaced with solid boards. Make sure to check with a mechanical engineer or your
building maintenance supervisor to be sure return air circulation will not be interrupted.

10. Communicating Doors (Airlock Doors)
Despite your best efforts to seal the door, it will always be one of the weakest link. The
wall construction is far more isolating than the door. The wall has more mass and no
concerns about seals. One excellent way to help is to create a communicating door
system. Two doors face each other to create an airlock. This works well when you have
a wider wall such as a staggered stud or double stud wall. Note: You will need to
accommodate the protrusion of the door handles.

11. Automatic Door Bottom
Another option is to install an Automatic Door Bottom to your door. This is
helpful if you can’t deal with the exterior jamb threshold or have a transition
in height (tile to heavy pile carpet) that won’t allow you to reduce the giant
gap under that door.

12. WINDOWS
To eliminate sound leaking through a single pane of glass, consider adding a second
pane of laminated glass. Use glass that is at least 1/4" thick and separate the two
panes as far apart as possible. Make sure your alterations do not compromise fire
codes and again compare the costs to installing new window units.
• For window panes that are loose in their mountings, re-glaze the openings or seal
panes to be airtight.