5k without receipts down to the last cent is probably not an issue at most banks, especially when it also involves outdoor facilities and/or other own contributions. However, it becomes more difficult the larger this amount is and/or the tighter the financing is. On the other hand, if you process all payments through an account at the same bank, you don't have to collect all the receipts extensively. I did not have to submit a single invoice this way; the construction was done with individual trade contracts, small items were ordered online and paid by transfer or card.