Wi-fi bridge from Apartment to Office in same building

Question

TLDR; Given my situation, is it possible to share my home internet connection from my apartment one floor down to my office using only wireless/wifi? Hypothesis is that I can use NanoStation and 900mhz band.

I have recently rented the small office/retail space on the ground floor of my apartment building. However, internet is not included in the lease. Nor will the landlord make it available even though the building is wired for fiber. Note: the office is not wired for any kind of telephony or Ethernet.

I live one floor up but on the opposite side of the building. Therefor I cannot simply drop an Ethernet cable down and hope my wifi signal reaches. I tried, but this 1930s concrete and plaster is difficult to work around/through.

For the past month I have been working in the office with internet tethered to my mobile phone. It has worked well except that I would like to have some of the machines in the office connected to the internet 24x7 for streaming, security, etc.

I am left with the following options:

1. Continue as I have tethering, but it does not solve my 24x7 want.
2. Obtain a 4g modem and router for the office. This is the easiest and path-of-least resistance solution. However, I don't know if the 4g speeds will be satisfactory for streaming 1080p to multiple channels (Youtube, facebook, etc)
3. Use more advanced gear (eg Ubiquiti nanostations) to bridge the internet from my apartment to the office.

I would like to discuss option three given the following constraints:

• Several solid plaster and concrete walls in between my apartment (floor 1) and the office (ground floor). The distance from door to door is less that 100 feet (30m).
• I do not have line-of-site between my apartment and the office.
• I do not have permission to holes or do any kind of cable pulls. Nor will I receive it.

Below I have illustrated the layouts and rough distances.

Top-down overview:

As stated the distance from the office to my apartment door is less than 100 ft.

Answer 1

WiFi should be capable of passing a few walls over that distance, but it depends on their material and the ambient interference.

Two strong WiFi routers, the office one configured as a repeater, might be enough. You might need to check for an unencumbered channel, and the speed will depend on the quality of reception, which among others depends on the walls in-between.

In my case, a non-exceptional router once worked for two-thirds of the same distance, and one of the walls was extremely thick. Much more powerful routers are available today.