Building materials is an important factor to built a house, to estimate funds the needs of build a house,
consumers or developers can estimate the funds needed to build a house. To solve these problems use
case base reasoning (CBR) approach, which method is capable of reasoning or solving the problem based
on the cases that have been there as a solution to new problems. The system built in this study is a CBR
system for determine the needs of house building materials. The consultation process is done by inserting
new cases compared to the old case similarity value is then calculated using the nearest neighbor. The
first test by inserting test data then compared with each type of home then obtained an accuracy of
83.6%. The second test is done by K-fold Cross Validation with K = 25 with the number of data 200, the
data will be divided into two parts, namely the training data and test data, training data as many as 192
data and test data as many as 8 data. K-Fold Cross Validation method. This CBR system can produce an
accuracy of 85.71%