Expanding upon what @John answered, wide doors are a necessity; additionally, because their legs are to the sides of their bodies, they will need wider hallways and such as well.
Until hydraulics are invented (for a slow-closing door), there would probably be few actual hinged doors, as they would be awkward to close behind oneself, and if the doors were not hung perfectly evenly, the door would try to close on their legs. For most dwellings, I would envision heavy or beaded curtains as interior doors, and sliding doors for the exterior (a primitive form would just be wood/stone/etc slabs with an indented "track" for them to slide in).
Regarding general architecture, since this species is likely adept at climbing due to their physiology, their society would likely start building vertically (multiple floors etc) as soon as the stone age, where dwellings might consist simply of holes carved into a cliff face, one on top of the other. This early adoption of vertical structures would allow them to quickly learn how to build load-bearing supports, and you would likely see arches and pillars featuring prominently in the architecture, and these supports would be the place for architects and even societies in general to express and distinguish themselves.
The species might tolerate lower ceilings than we generally do to conserve space and materials, since they require a greater floor space to have human-equivalent activities. A family of four of these creatures (assuming human height and proportionate leg span as per your render) eating dinner together would not be comfortable in what we'd consider a moderate-sized dining room of maybe 11x15 feet.
Space could also be saved on stairwells for multiple levels, as you could just have holes between the levels with rough wall surfaces to assist climbing (consecutive holes would not be vertically aligned though, to reduce the risk of injury in case of a fall). Outdoor "climb walls" would probably be more prevalent than outdoor stairs are for us, as it would provide easy access to the upper floors of a structure from outside. There may still be indoor holes/climb walls so they don't have to go out in the elements to go between floors (as well as for security/etc), but outdoor alternatives might seem more appealing.
As mentioned by @John, floor surfaces should be coarse and/or soft. Depending on the technology level, loose gravel might make an ideal floor surface for a primitive race, and this might evolve to mortared gravel to create a bumpy surface with rough spaces in between, while eliminating the issue of gravel getting pushed around/kicked up/thrown by children or miscreants.
Chairs would not have backs; cheaper or more primitive chairs would simply be pedestals to rest their abdomens on, while more advanced chairs would be curved on the sides, and possibly slightly curved up toward the front to provide support to the upper abdomen and "hip" region (the part that resembles a pelvic bone).
On the topic of furnishings, tables would be smaller relative to the room size than we're used to, because a large table in the middle of the room can easily prove unwieldy to navigate around. For this reason you might see tables situated against the walls more often than in the center of the room.