Q: Is it possible to add a room onto an existing earthbag structure and, if so, how would it be accomplished?

A: The best way to add on to an earthbag house is to prepare for that possibility in advance and place a dummy doorway where it might be needed. This way it is a relatively simple matter to plaster over the door until you want to make the addition, and then just knock out the bags in the doorway with no concern about collapsing walls. Otherwise, it might be necessary to carefully brace and provide support for what might be above the doorway (or window) as you remove the bags in the wall.

How would one attach the walls of the new addition to the walls of the structure already in place? I mean, would it be necessary to physically attach them or would it suffice to butt the new wall up against the old one as long as it is tamped and buttressed and the gap sealed properly?

In most cases simply butting the walls against each other would suffice, but to assure that the connection is as cohesive as possible, you could pound rebar stakes into the old wall in such a way that they get embedded in the new one. Also, if you use some bent wire mesh to connect both sides of the two walls before plastering, so that the new plaster tends to bridge the two walls together, this will help.

Q: Would it be possible to extend an existing building using earthbag construction?

A: Yes, you can connect an addition of earthbag construction to an existing building of another design. At the juncture between the two methods care needs to be taken to make sure that the bond is solid and will not separate over time. This can be done by providing physical connections with steel rods, barbed wire and/or mesh in plaster that bridges both surfaces.

Q: I want to ask your advice as to the best way to tie in an earthbag extension to an old stone house, granite with rubble infill walls?

A: I would think that you could tie those two walls together by periodically drilling into the stone wall enough to embed some sections of rebar at the level where they could lay between courses of bags. Most likely the easiest place to do this would be in the mortar between the stones.

Q: Our back wall remains standing strong at about 6 ft height. How best can we attach a new earthbag wall to this existing wall?

A: It is usually possible to successfully connect a new earthbag wall to an old one by using steel rebar pins going through the new one and into the old one. If they are driven at various angles they can effectively connect the two. In addition to this I suggest that whatever mesh is used in your plaster is continuous from the new to the old, so this will also help hold it all together.

Q: How do framed walls connect to an earthbag wall (&/or floor)?

A: You can attach a partition wall to an earthbag wall in several ways, either with threaded rod going through both and secured with a large plywood washer on the outside, or  putting wooden or metal anchors in between bags when the wall is build that can later be attached to the wall.

Q: I built my earthbag home in rural Nicaragua last year. I would like to know how I could be able to add a doorway to the wall on right of the image shown below. It doesn't bear the weight of the roof but it does contain pins, barbed wire, and dried earth bags.

A: This is why I advise that people put temporary or eventual doorways in while building with earthbags. Retrofitting a doorway can be done, but only with a fair amount of difficulty. You will need to first cut through any plaster and the bag material along the wall where you want the doorway to go. Then it will be a matter of carefully digging out the fill material with trowels or spades. Whenever you encounter barbed wire, it can be cut out, especially at the margin of the door. Metal stakes might be temporarily left in until you can work them loose and pull them out.

It helps that you have a good concrete bond beam at the top of the wall to help support the wall. Hopefully, the higher bags above where the door will be will stay in place until you can install some sort of lintel over the door, probably supported by vertical framing on either side of the door. This means the doorway needs to be cut large enough to accommodate all of this framing. Eventually mesh material can be attached to the door frame and stretched over to blend with the rest of the wall before any replastering is done.