What is the weight limit on the Birch Foundation? February 18, 2021 18:13 The Birch Foundation can support up to 1,200 pounds. Related articles What’s the difference between Birch and Birch Luxe? What are the dimensions of the Birch Foundation? Does the Birch Mattress require a foundation? How much space is between each slat on the Birch Foundation? What's the weight limit for the Birch Kids Natural Mattress?