We have a lath and plaster wall that has cracks and bubbles which have occurred over a period of about 10 years. It is confined to one wall and there is a large window over the area but we see no evidence of water damage or leaks.

Our home is located in a cold climate and not in California where there would be obvious termite damage.

Not sure if I can submit a pic on this site but if someone needs me to see one we can email a pic top you.

Your thoughts and ideas please.

Pics on this site is not only allowed but greatly helps all who see it. Big Temperature change and add some higher moisture in with that and that mix can help cause a plaster bubble. Either or the bubble needs to be taken out and check for insulation in that area and condensation. It doesn't take a lot of water leaking around a window to cause a bubble. I live in an old town where this is very common in time. Its either moisture or age and house shifting that causes this. Usually Its moisture. Remove old section of bubble plaster once it bubbles that's it for that spot. Check caulking around outside of that window and check the top of the outside window. If it's a brick home and old brick check all mortar joints in and above that window and that whole wall area If it is and all brick home chance's are the plaster is right on the brick and the old brick themselves is sucking in too much moisture and a brick exterior sealer is in order. When all is checked and addressed and you are ready to patch usually if you use drywall its not going to be the right thickness no matter what. You may have to shim out the drywall to meet the finish surface around that area. Now if you want to do it the old fashion way I posted a website for a material called "browncoat' Sructo-lite that you can find at your masonry supply house. This is the base coat that goes on the lath and builds up nicely to get close to the original finish wall thickness. Now, you don't have to use actual Plaster to finish that area. You can use drywall compound in place of the 1/8 or so plaster finish coat.
Again Moisture is usually the cause of plaster leaving the lath whether it be from a direct leak or pour insulation in that are and an air leak. I run into this on a weekly basis on our rehab job sites constantly Our town 17554 and ALL old city homes here are Brick and plaster and all interior walls are lath and plaster

Structo-Lite Basecoat

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