I did love house of leaves when I read it, but I also found it kind of weird how slavery is never mentioned. I'm not American, though, so maybe I lost some subtext? Anyway, I would love to hear your thoughts on the matter once you finish the book!
This is going to be long. The more I think about it, the more I’m just kind of stunned at the extent to which the architecture as grief and haunting and trauma and history book completely doesn’t at all address the fact that the house in question is a plantation. Two story three bedroom houses built in the 1720s in Tidwater Virginia right next to the James River are not anything else.
They talk a lot about how it’s haunted by Virginia history, but exclusively contextualize it in the story of the lost colony of Jamestown and the starving time and the pain of white settlers, which aligns with the house-as-frontier motif that characters like Holloway and Wax fit into. The Navidsons and Holloway and the Jamestowners all go to a new place in hopes that it will change them but instead, it really only reflects them in a positive feedback loop that is ultimately self-destructive. 
There is no mention of Jamestown as the place where slavery started in the United States. There is no discussion over who would’ve built the house built in 1720 even though there’s only one answer.
I think this itself can work as a metaphor for how the state of Virginia deals with its own history in terms of modifying it without acknowledging any of the darkness and evil that it took to build it. The book does straight up do this but again only in the context of white settlers.
The sentiment expressed here about colonial Williamsburg is real similar to how I feel about the Navidsons moving into a plantation house built in 1720 that has been recoded and reinterpreted as a sanitized cookie cutter nuclear family single home whose dark past on that front goes completely unremarked upon. But he’s talking about Williamsburg omitting the starving time and brutal struggle of the British colonial project instead.
I’m still really struggling to wrap my head around why any discussion of slavery or race is omitted in this book about architecture and haunting and Virginia. “There’s an integral part of this house that we do not talk about or acknowledge, but it’s in here with us and we are haunted by it” while living on a plantation feels like a setup that is so obvious to me in a way where I kind of have to wonder if its omission is deliberate. I think if you want to be generous you can make the argument that some of it is metacommentary on the silence of white inhabitants and interpreters of spaces like these?
White academics often have deliberately cultivated blind spots for this sort of thing where in the book thousands and thousands of academic journals are written dissecting every aspect architectural and metaphysical of the house as well as Navidson’s pain and trauma while the pain, suffering, and entire presence of enslaved laborers who built the house is a non-entity in the story. In the universe of the book people have called Karen Green‘s 87 affair partners to ask about her psychological state as a child and no one has written on who built the house. 
I think if we’re talking about space and place it’s also worth pointing out that contrary to popular (white) interpretations of the history of slavery, enslaved people not only built plantation houses, but also inhabited parts of them as well when forced to perform domestic labor in lieu of or in addition to agricultural labor. I say this because who and what is living in the house is a really big element of the book. It’s not just the structure and architecture of the house of leaves that gets remarked on, but also the presences and absences within it. The misconception that all enslaved people lived separately is often used by white historians to get out of having to talk about slavery and architecture altogether. No one in the book at any point considers any of the inhabitants of the house that weren’t previous presumably white owners.
There are a lot of white Virginians who have a tendency to pretend like local architecture just kind of manifested itself into the world (see: Monticello getting interpreted as like a Jeffersonian genius brainchild when the blueprints are quite sparse enslaved architects designed the house.) Similarly, at one point in house of leaves one of the sources used insinuates that white settlers just happened to find it in 1610.
Using the history of the house exclusively as a selling point or interesting fact like the realtor who sold the house to them did while they contextualize it as this bucolic white suburban getaway fresh start reminds me of the many plantations I’ve been to in Virginia that recontextualize and commodify themselves for white audiences as other things whether that’s “restorations” that anachronistically reinterpret slave, housing as “sharecroppers cabins” or “guest houses,” or plantations branding themselves as bed-and-breakfasts, wedding venues, or single-family houses. 
But on the other hand, it’s really hard when every other aspect of the house and its structure and its meaning and it’s history EXCEPT its historical context about slavery goes explored or commented on by the Davidsons or the academics interpreting this documentary or Zampano interpreting the academics or Johnny Truant. Why isn’t who built the house a bigger deal?
TLDR: Complete total lack of commentary about slavery in the architecture and trauma book where they live in a plantation house is definitely of reflective of the pattern of erasure of black trauma and accurate history from academic and architectural spaces. Whether that’s deliberate commentary on erasure or just wholesale participation in it is up in the air for me.