Meeting ambitious manufacturing targets for the Model 3 required what Elon Musk memorably dubbed “production hell” and a relatively impromptu tented production line. Despite the doubters, Tesla managed to ramp up in time to hit its 5,000-car-per-week goal by the end of June by a margin of just 31 Model 3s. Now, it seems a similar ramp-up is underway to help fill a staggering number of orders for Tesla’s solar roof.

This is according to a Bloomberg report about the Tesla’s controversial facility in Buffalo, New York, which details some of the hurdles in getting the solar roof, first presented with Musk’s typical flair on a former Desperate Housewives set, ready for the market.

Despite the expense — building a high-tech roof can easily run you six figures — Bloomberg reports that Tesla is still trying to deal with the more than 11,000 orders it had already received by May. It’s unclear how many solar roofs the company is producing already, but the facility is now manned by multiple 80-employee shifts so that it can churn out solar shingles 24/7.

Even making the solar roof’s prototype presented a number of interesting design and technological challenges (strangely, if you’re going to convince rich people to roof their homes with solar panels, they need to look nice.) One of the most fascinating tidbits from Bloomberg’s reporting is that Musk apparently scrapped the initial prototype of the solar roof just two weeks before the official announcement, forming an ad-hoc team tasked with designing something better.

Making solar panels aesthetically appealing was no easy task. You essentially have to “camouflage” the technology within them so that they still look like normal tiles from the street. To figure out a way to do this without undermining the solar panel’s efficiency, Tesla engineers had to figure out the right way to literally sandwich the components together without creating air bubbles. After some 74 different variations, Tesla found a combination that it says works by the end of last Spring.

Despite promising feedback from early adopters, scaling up Tesla solar roof production has proved a challenge. Tesla

There are already a few Tesla solar roofs out in the wild, in addition to the prototype that was initially installed on Musk’s own guest house. Two of the solar roof’s earliest customers shared the installation costs and energy savings with Inverse over the summer and say the roof is worth it, if you’re in the market for a roof.

One Nvidia senior manager claimed to have spent around $35,000 more on his roof re-installation to make the upgrade to solar, and his utilities bill dropped from $350 per month to around $90. Another early adopter in San Jose claimed over the summer that, during the California heat, her solar roof was capable of generating a surplus even while running the AC.

With these early engineering kinks worked out, more orders than it can fill at the moment, and a manufacturing pipeline starting to take shape, Tesla’s SVP of Energy Operations Sanjay Shah told Bloomberg it was gearing up for “tremendous growth in 2019.”