Loft and patios are very similar.
The choice is personal preference and may be influenced by your guinea pig’s personality and age.
The Loft is popular. It is a stationary structure that is made of grids which sit in the connectors atop the base cage grids. The ramp is recessed and comes precut on the left side with edgers to prevent chewing on the sidewall. The loft allows for a full, large hayrack underneath.
The patio sits mid-grid height and is supported by two of our flat and strong Wonder bars, so it easily lifts off to clean underneath. You can adjust the height of the patio a bit up or down which gives you a little more control over the ramp pitch. The Patio ramps are less steep which can help with timid pigs or seniors. The Coroplast is not precut for the ramp which allows you to decide where to put it. The patio provides less headroom when covered. If you do not have a cover, you can provide additional height with the optional perimeter safety grids. You'll need to use loose hay piles and/or a hay bag under the Patio.
Either solution adds great enrichment for your guinea pigs and helps keep them happier and healthier with more space and better exercise.