Converting a duplex to a single family home

What all would be involved in converting a duplex back into a single family home? Removing a few walls and getting rid of one of the kitchens, yes, but beyond that?

I’ve been house hunting and seen some houses that would be absolutely perfect except they’ve been divided at some point in the past into duplexes. At the moment, I’m not considering them, but if the cost of rejoining them isn’t too great I just might start.

What would need be done? What would you suppose it would cost (roughly) to do it?

On a side note, is lead paint a problem? All of the disclosures I’ve read insist that the owner is unaware of any, but it’s quite clear that nearly every house in the area has it. What about asbestos tiles?

Are there any laws against heating with coal? One house I really like has its original coal furnace. It’s got a modern oil one, too, but they say they use the old one when the power is out as it doesn’t need any.
This all applies to Farmington, in Franklin County, Maine.

This is some WAGs based upon the experience my wife’s parents faced. They bought a house that had been converted into a duplex, and they turned it back into a house.

The big question is what the wall separating the two units is composed of: a standard interior wall (in whether it’s a load-bearing wall), or a thicker exterior-type wall (which would take more work busting through). If you have a contractor or an experienced DIY, it shouldn’t pose a problem.

Now the utilities: does it have separate water meters, separate power meters? I suppose it would be easy to leave them alone and simply pay two bills each month, but if not, you’d have to hire someone to fiddle with the plumbing and wiring, and the respective companies about removing the meters.

Lead paint: Care should be taken if you’re using a heat gun or sander on them. Wear a good dust mask to keep the powder from getting into your lungs (not one of those basic masks, one that has screw-on type filters). Painting over them is possible, but be aware that your state may have strict laws about lead paint (I know, from watching “This Old House” that Mass. has very, very strict rules, but I’m not sure about Maine.)

Asbestos tile: If you’re talking about the type that is used as siding, they’re fine, so long as you don’t break the tiles. That releases the asbestos fibres that can get into your lungs and cause all kinds of nasty problems. I used a power washer on my house (which had these tiles) to blow paint off them; that’s safe. Then I caulked and repainted. The only problem I had was that it was expensive to replace the broken tiles, since they were scare in my neck of the woods (South Carolina).