Our fieldstone foundation (1913) has some areas that require repair. Stones are loose, and there is a badly filled hole that use to accommodate oil pipes. What type of mortar should we use to repair this? Thanks!
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the rest of the crowd will be in - in another hour or two....
then there'll be some more activity..
is this foundation dry packed, mortared or stacked??? (how was it put together originally)
what is the type and shape of the stones??? round, flat or chunks???
was the pass hole cut or original???
can you post a pic???
Thanks for your responses. The foundation is built out of mortared round and chunk stone. I'm pretty sure the pass hole was cut, as the house was originally heated with coal and the hole was cut for oil delivery. I am attaching some photos. The "eyes" on the exterior are the old oil pipe holes and the large patch with the small hole is the interior of that area. The clean looking exterior (with fern) is the outside face of the badly damaged interior (with colored rug below). This hole is the result of my husband and me "picking" at the crumbling mortar that we tired of sweeping up. We have all the rocks we pulled out and the breach does not go through to the exterior. So, we want to put things back together again. Thanks for your help!
I tried to open those pics but the system timed out before I could see them...
Hopefully someone with broadband or DSL will download and resize them... so now I wait....
let's guess as to what you have and are tring to do...
take the type M 1st and the type s as a 2nd choice. repair the hole with concrete mix with just enough water in to make it workable...
Type M. Type M mortar is composed of 1 part cement, ¼ part lime, and 3¾ parts sand. This mortar has a high cement-to-lime proportion that makes for a very strong mortar. This type of mortar is suitable for general use. It is recommended specifically for structures that are below grade and in contact with the earth, such as foundation, retaining walls, and walkways.
Type N. Type N mortar is composed of 1 part cement, 1¼ parts lime, and 6¾ parts sand. Type N has excellent workability because of its high lime content. It does not have the strength of Type M or Type S mortar. Type N-
Type O. Type O mortar is composed of 1 part cement, 2 parts lime, and 9 parts sand. It is extremely plastic and workable (notice the lime content) but has relatively low strength.
Type O should not be used if it will be subjected to freezing and thawing in the presence of excessive moisture. Many building codes do not allow Type O mortar for construction. However, some local building codes allow Type O to be used for load-bearing walls of solid blocks when the compressive stresses do not exceed 100 pounds per square inch. Before using this type mortar, check local building codes.
Type S. Type S mortar is composed of 1 part cement, ½ part lime, and 4½ parts sand. It is a very good general-purpose mortar used in above-grade exteriors that are exposed to severe weathering. Type S is also used in interiors and all load-bearing structures unless only Type M is specified. Type M and S are usually interchangeable.
When old Mr. Yerby redid the foundation of my parents' place ca 1966 he used a lime-free mortar -- just sand and cement. According to him, lime on creek limestone didn't hold properly (and the old stuff that he despisingly called "brick mortar" was indeed disintegrating into dust). The guy was probably 65-70 at the time and knew his stuff.
As of about 5 years ago the foundation was still in good shape.