New shutoff valve, add a PRV and probably some water hammer arrestors on both hot and cold, or just the cold at least. A one way directional valve fitting would eliminate anything happening behind it, if you install it right after your shut off valve. Had to add a one way valve fitting right before my tankless fitting since any time any cold water was used the water heater would turn on from the tiny amount of cold water moving.

One other thing a lot of people forget. You have to clean out the holes. Those bits don't clean out the hole like a normal drill bit in metal or wood. You need to blow or vacuum them out. You're 3" hole can be filled with debris in the bottom inch. This applies no matter which method of fastening you use. You especially want the hole clean if using epoxy.

Not necessarily. If they were two separate rooms they would have had two separate vents regardless of square footage or one room would have no heat/ac. The two small bedrooms in my house have 1 vent each, but my bonus room is bigger than the 2 of them combined and does fine with just 1.

Generally you go 1/8" larger to make sure there is room for the epoxy all around. Check the size of the mounting holes on the posts. If they are half inch, you can increase the size of the threaded rod a bit - I would go up to 3/8" rod, and drill 1/2" holes (leaving 1/8" to fill with epoxy). You want a little "wiggle room" to get the spacing of the studs right and to fill all around with epoxy. Read the Hilti instructions - they are good - and there are some youtube videos. This is a very basic video, but shows the process (you don't need the extra step shown after using a core drill - that is something unusual) - the related videos below it are also good - https://www.youtube.com/watch?v=TsonKFh0UUw

If you are doing something that is fussy, transfer the pattern to some plywood, drill the same hole pattern in that, and hold the studs in place with two nuts (one on each side of the plywood) and make sure you can get that in and out of the drilled holes without binding up. You can even leave the plywood in place during the glue cure (just don't accidentally glue the nuts or the plywood to the concrete!).

You still have the same requirements to clean the dust out of the holes, using a small brush (I stole the brush that came with one of those reusable straws my kids had to have...) and some compressed air. Vacuuming can be part of it, but it won't get the dust out of the very bottom by itself. Sticking a thin tube down to the bottom and blowing it out with compressed air is better (but don't breath the concrete dust!).

It is going to need to be replaced, its broken and you'll have to buy a new one... so use a large channel lock pliers and literally twist and break the door knob completely off. Remove all the remaining parts falling off to access the interior mech. of the door knob. Manipulate the latching mechanism to open the door with needle nose pliers.

Go to home depot or lowe's to buy a replacement.

Hey thanks appreciate this. I’m calling them tomorrow. -30C, ouch. Will post back once we get to the bottom of it in the next week or so.

They were Titan fasteners. This is great advice, thanks so much! I’m in the US and will buy the epoxy you recommended. If we use 1/4” threaded rod (since that was the size of the original fastener) do you have a recommended bit size? I’ll definitely be renting an SDS drill too because I can’t go through that again…

That square footage needed two ducts before and the lack of a wall won't change much.

Leave the second duct and pinch them down with with the damper on the diffusers if needed.

You can try any or all of them. Anything will help and more would be better.

I think the latter. I can’t feel wind or anything so I assume it’s just letting heat escape through edges and window on the door.

Curtain and the clear plastic is a good combination. The clear plastic helps trap air in which works as a bit of insulation.

Clear bubble wrap on the windows will give some insulation and let light through, but you can’t see through it.

Is the door drafty or just conducting too much heat?

This is great advice. What diameter is the best for the steel threaded rods?

Heavy insulated curtains in front of the door work wonders. Arrange them so they go floor to ceiling, and are close to the wall.

I've used that metal double bubble insulation over really poor windows and doors before (in rentals, where I wasn't going to spend much money). Tape all around the edge. It cuts out all the natural light, but definitely helps with the heat loss.

You can also get "window insulating kits" with some plastic film you tape around the edges and heat a little bit with a hair dryer to get it tight and decent looking. Not as good insulation, but you don't lose the light.

They are absolutely fantastic for making holes! Also crazy good for removing tile (with a flat chisel bit). Just pick some other concrete fastener...

Oh shit, well that halts my own desire to splurge on an SDS for tapcons then. Guess I’ll have to find another use to justify it hahah

Rent an actual rotohammer and use wedge anchors. If you still want to use a concrete screw, use Titen instead of Tapcons. Make sure you clean out the hole after drilling via compressed air. If you choose to use an epoxy option as one person suggested, use both compressed air and a wire pipe (tube) cleaner to clean the holes.

Titen is a better product for screws into concrete if you don't want to use wedge anchors.

35 and up is now considered high risk pregnancy ! Time is a ticking.

I fell for all that, too. Tried a better drill. Bought the special Tapcon bits and drivers. Cleaned the hole like we were doing surgery.... still broke 2/3 to 3/4 of the damn things...

I don’t disagree. What I meant though was an SDS results in a better hole for the tapcon and more successful driving. At least that’s what I have been told. As I said I don’t have an SDS

My house is built like this. Built in 2018. The HVAC has 3 zones, 1 for the master, 1 for the living room, and 1 for the 2 lesser bedrooms on the other side of the house.

It works great when I'm just chillin in my office/game room and it gets toasty, I can just close the other 2 dampers so that only the game room is fed all the cold air I am requesting. And because I'm only cooling a small room thats about 350sq-ft at most, it cools it off pretty damn quick. Also helps that each zone has its own intake vent also

I have both conventional hammer drills and SDS. It's not the drill. Tapcons stink no matter what.

After working in telecom/IT for so long now I decided if I ever build or renovate a house I am putting in a home equivalent of a BAS system.

Multi stage heating and cooling, PWM controlled supply fan, dampers to limit airflow from the air handler all so each zone can be set to different temps, but keeping the static duct pressure in the optimal range.

Measure the water pressure, of it's above normal (google it) you'll need that pressure thing, the arrestor is definitely a good idea but it should be after the valve not before.

My guess is there is a leak on the city side, call the city and ask to close the valve on the city side

It might be too late for this, but in my own experience fastening to concrete I definitely prefer wedge anchors to tapcons. If you have a nice SDS I am sure that tapcons are lovely, but for my uses I either strip the hole, snap the tapcon, or it drives perfectly. 1 in 3 worked for me so until I started used wedge anchors.