IF YOU ARE STARTING FROM SCRATCH ....CHECK OUT GOETHERMAL SYSTEMS
YOU GET HEAT AND AIR FOR THE LOWEST POSSIBLE COST USING THE GROUND TEMP OF 55 AS BASE

Any water coming in from the bottom is first coming in from the top...running down side channel and overflowing bottom channel. Seal top and sides and bottom will take care of itself

The only way to get to all of the wall cavities is from the outside. It would also allow you to install vapor barrier and check for any areas of water damage. Although styrofoam has a better R value, any gaps allow air penetration which is worse. Definatley use fiberglass and install with attention ...

Did you say you are painting the tongue? Most homes I have seen simply unbolt them and store them underneath....out of the weather

I agree with Rod...you have to get more air flow between the roofs and make sure the original venting is not blocked. You basically have 2 vapor barriers and that is your problem. The dew point (where cold meets hot) is supposed to be on the outside of the roof insulation so adding insulation on top...

The fact that the clunking is consistant with heat/air on or off leaves me to believe that it is from water or electrical. Those are the only "active" systems on all the time. Electrical would have to be a motor, fan bad fixture in the crawl space. Plumbing could be water line bouncing off...

Use a siliconized/acrylic caulk (like polyseamseal) after laying in adequate bead, finger in to seal to sink and top. To finish off...just take a wet sponge and wipe gently removing eccess (sp?) until desired look is obtained

You might try covering the wall with acoustical tile (cheap and easy) If thats not enough then you will need to insulate wall, add sound board (acoustical tile) and redrywall. If thats not enough you will need another wall built inside existing wall using the same process.

Your problem (I think) is the plastic you used. If you put the plastic behind the insulation, condensation is forming on the warm side.Typically, you install insulation and then plastic but if the plastic is not air tight you will still get condensation. You should have vents in the roof....this kee...

Be verry careful as to the glue you choose. Some glues will actually melt your flooring.
You need a perimeter glue ideally made by your particular floor manufacturer

I have installed dozens of pocket doors. They leave no room for electrical and retrofit needs removal of twice the width of the door to fit the pocket. It is also set up that you need a full 2 x 4 wall to work. I guess you could install it on the outside of existing wall if you have 4" to spare

There are companies that can give you an exact replacement for your fan motor (or rewind yours) so dont trash the housing yet.
Hooking it back to ductwork is not fun

Whole house water filters come in a wide variety of sizes and specific filter/condition Size conforms to how much water you use (too small of a unit causes excessive filter changes which gets costly) Condition conforms to what chemical your trying to eliminate (different type filters for different e...

I have found that replacement windows is easier when you order exact size to fit opening.(dont forget LowE and Argon) I have to pay helpers and time is expensive. I think an inexperienced person could do the job if they were exact size however its a trade off for the more expensive window. You might...

The freezing would have had an immediate problem...like a cracked bowl. Sounds like an item is lodged in the trap. Try a metal coat hanger and put a small hook on the end and try to retrieve the blockage. The only other thing could be a clogged vent but doubtfull