The upgrade comes soon after a new front wing was introduced at Silverstone as the team tries to improve its performance in the wake of the recent huge leap made by close rival McLaren.
The team had a strong run when Esteban Ocon qualified fourth and finished third at Monaco, while Pierre Gasly was fourth-fastest in Q3 in Spain before being hit by a six-place grid penalty.
However, recent weekends have been frustrating, with the team lacking pace and logging consecutive double retirements in both Britain and Hungary.
Often when update packages come in stages the full picture isn’t seen immediately, although in this case the team stresses that the front wing wasn’t waiting for the new floor in order to fully optimised.
“The floor is independent of the front wing,” said Alpine sporting director Alan Permane when asked about the upgrades by Motorsport.com.
“It’s important because we need to keep putting downforce on the car and moving forward and going faster, basically. So it's very important. It isn't linked to the front wing, but it's a very significant step for us.”
Regarding future updates, he added: "There's definitely a large upgrade for Singapore, but I think there'll certainly be smaller stuff for example in Monza as well.”
Over the last two races Alpine has slipped behind McLaren in the battle for fifth place in the world championship, with the Woking team’s 58-point haul over the British and Hungarian GP weekends giving it an advantage of 87 to 47.
"McLaren have done an incredible job,” said Permane when asked if McLaren’s surge provided inspiration.
“Hats off to them, honestly. If you look from where they were in Bahrain, to where they've come to, it's almost like that this is where they should have been, and they were suffering before.
“It's not normal to make such a huge step like that. But even so, they've done a great thing. We are of course looking at everyone, but mainly focusing on ourselves and our own model in the tunnel, and bringing the upgrades as fast as we can.”
Asked if the team is still aiming to have the fourth-fastest car, he added: "That's our target. That's our plan. And we will just keep developing as hard as we can to try and achieve that."
At the Baku sprint weekend, Alpine was caught out when it brought updates and had problems in the single FP1 session before heading into parc ferme prior to qualifying, and thus the set-up wasn’t optmised.
Team principal Otmar Szafnauer is hopeful that the new floor won’t compromise the Spa weekend.
“I hope not,” he said when asked if Friday at Spa might prove stressful. “We will still bring the floor as it is more performance and it is around two tenths of a second per lap, whatever it is, a new floor, so we will put it on.
“But you are right, we have a short period of time to assess and analyse it, but on that side of it we have good tools to assess it. The floor will be instrumented so that we can see if it is sucking more, and how many points of downforce we get out of it.”
