Concerning about having construction work done by someone other than the house builder's partner.

Worried about having construction work done by someone other than the house builder's partner.

It seems to me that since the exterior work is incidental, I can commission it privately, but...
The amount of money is big and I don't know much about it, so I am worried.

We do it perfectly

We will thoroughly discuss with you until you are satisfied with our services, and we will resolve any issues or concerns that you may have.
The same sales person will be in charge of the project from the first meeting until the completion of construction, so there will be no problems during the construction process such as not understanding, not listening, or not telling.
We will leave the construction work to skilled craftsmen, but we will manage the work thoroughly.