Custom home builders shop for raw materials needed for construction in a different way compared to regular home builders. First and foremost, they almost always ignore the high profile stores such as Home Depot. Instead, they choose pro-suppliers who are mainly in the business to serve builders who work on custom home development projects. On the other hand, regular home builders normally buy from big stores.
There may be many reasons why custom home builders buy their products from pro-suppliers. There is a general talk in the construction industry that the quality of products available in big stores is not that good. But, I don’t think there is much truth in that. The materials available in big stores are of reasonable quality. Their prices are also quite competitive. But, one of the main reasons why custom builders go for pro-suppliers is that they are specialists. Home depot and similar stores are mainly there to sell to retail customers. Their business is not geared towards home builders. Some regular home builders get away with buying from the big stores. But custom home builders always buy from pro-suppliers since they often want their materials in a specific way and they have more precise requirements.