Thinking of buying townehome next door and opening up wall between us to make liv/din area. I was told it's a firewall between attached homes... can it be opened up to make an arched doorway between rooms. Is a firewall concrete?

Most firewalls in condos are double layers of drywall, so its likely possible. However, check with your HOA, if you have one, and the city Building and Zoning to see if they will allow it.

In my area a firewall's constructed out of cement block and runs from the slab past the roof line. While it's passable to convert two condos into one it must be approved by the Building Department first.
Good luck, Tom

Unlike duplexes, townhouses are considered separate buildings on separate lots by law and cannot normally be combined as the original poster wishes.

And where they might be permitted to be combined, cannot be so done without going through a very expensive legal process that involves the local Planning Commission and Zoning Board to create a major subdivision improvement, redrawing of the maps and deeds for the 2 buildings and the development involved, and a host of major Code required changes that will require remodeling changes to combine 2 separate sewer, water, and electric systems into 1.

If allowed, it could cost tens of thousands of dollars to combine these separate buildings, and therefore be cost prohibitive to most.

Sorry.

Manhattan,
Perhaps it's that difficult to join two units to make one large in your area but here in Florida we do it all the time. Especially out on the keys where large cooperations will purchase two beach side units and cut in a door way. Back in the 70's and 80's we were busy combining Gulf side motel units into time share apartments.
Different areas have different codes and rules. You simply can not take one set of codes and then make a blanket statement to cover everybody such as you just did. Regards, Tom

The same Codes apply in my state as in Florida. And pretty much every other state in the US:

Townhouses are separate buildings on separate lots with separate deeds... and firewalls are required by Code between separate townhouse units. Period.

Townhouse developments are also created under their own subdivision and planning rules and units cannot be combined willy-nilly.

No more can one buy a townhouse unit next door and just connect them, than can one who lives in a single family house buy the single family house next door and connect them with a breezway.

It would first take a major improvement subdivision permit from zoning and planning to combine the two deeded properties into 1 deeded property before building permits could be issued to perform the structural work to remove the firewall.

Deeds would need to be redone, subdivision maps redrawn, hearings paid for with the local authorities, lawyers hired...

And all that adds up to a large amount of time and money... with no guarantee the original poster's request for consolodation will be granted.

By all means does the orignal poster need to speak to his local building and zoning authorities, but he should be fore-armed with the knowledge that what he proposes is a building code violation and not allowed as he now envisions it, and to rectify the situation will cost him 1000s and 1000s of dollars to first combine the 2 separtely deeded townhouse parcels into 1 before a building permit can be issued to remove the firewall... and only if his municipality will allow it.

Sorry.

This may depend on the precedent in this particular community. Firewall, have other townehomes in this in this community been combined? I would check with the homeowner's association and closely read the covenants/restrictions and see if what you propose is strictly forbidden. I believe that manhattan may be correct. If you are the first to try this it will likely be a legal and financial nightmare to pull it off, even if the construction project may be fairly straight forward...

In my opinion, I would do as you wish and not tell anyone.
If you sell, you may have to close the openings and do it right as it originally was.

Still, without giving yourself away and bringing attention to yourself, find out what complications there may be.
Do it all legally if you can do so reasonably.

Not the best direction to take, We have building codes for a reason. Some for safety and some for health, but all are important and should not be ignored. Regards, tom

I agree with Tom.

Check with the home owners association and building department to see if OK. If yes, proceed from there.

Chuck