Lead generation for a construction company that grew on referrals only, how do you build consistent lead flow

Our close rate is like 8 out of 10 which I know is strong for window installation but it doesn't matter when the phone only rings 8 to 12 times a month. Almost everything comes from past customers telling people about us and some months that's 15 calls and other months it's 5 and I have zero control over any of it.

Tried google ads a while back, spent a ton and mostly attracted people shopping for the absolute cheapest option who would ghost after the estimate. Did door hangers in neighborhoods where we finished jobs, got maybe two callbacks total. Website looks decent but it just kind of sits there not really doing anything. Nothing I've tried comes close to a referral lead quality wise and I get why, when the neighbor vouches for you the trust is already there before you walk in the door.

Something that came up while working through this with cultivate advisors is that I never even built a system to generate referrals on purpose, I was just passively hoping they'd happen which in hindsight is kind of embarrassing. The "marketing engine" I probably need isn't some fancy campaign, it's a structured way to consistently ask happy customers for referrals while building other stuff around that. But the execution part is where I'm lost.

Anyone in trades or construction who went from pure word of mouth to consistent lead flow, what did you do? How long before it worked? I can't afford another expensive experiment that goes nowhere.