You fix the problems outside you wont have a problem inside

 https://ampmexterminators.com/am-pm-seattle-ants-control-removal-service-exterminators-get-rid-of-ants-in-homes-or-commercial-business-buildings/

These are just recommendations on preventing ants from getting in the house. Treating the immediate perimeter around the main building regularly during the warmer months might slow down scout ants searching for food sources in the main house. We not responsible for any developments to the property as result of this report. 

Avoid vegetation as its easy access for ants to access the main building

Those pavers are considered moisture barriers which would harbor ants in the warmer seasons. You wanna gravel or sand those tiles 

Excess moisture under pavers with no gravel or sand will attract ants in the warmer months

Avoid vegetation contact to the building. The little fence connects the vegetation to the main house

Avoid vegetation contact to the main building

Avoid earth to wood contact . As its attracts ants from the moisture build up

Sealing the pavers might be a cheaper solution to keeping moisture out of the pavers to prevent ants from nesting under the pavers. Revision of drainage

Indicators of moisture barriers attracting ants in the warmer months. 

Sand kick out of the pavers is an indicator of pasted activity

Green moss between the pavers is an indicator of moisture barriers that attract ants in the warmer months. Recommendation gravel and sanding the pavers.