Why an inner tent?
When it rains, is damp, and/or cool, we strongly recommend an inner tent if you do not have the opportunity to use a wood stove. On particularly windless days with a lot of rain, you will experience condensation on the inside of the outer tent as it is somewhat difficult to get rid of the moist air. Also. With an inner tent, the need of seam sealing is perhaps not that essential.
This is also the reason why most tent manufacturers with silicone-based fabric do not inform about seam sealing. As the inner tent that comes with the tent nevertheless keeps a distance from the water that may occur on the inside of the outer fabric.
However, For many of our tents we offer you a choice to use an inner tent, or not. Where we do recommend seam-sealing the seams as the seams on silicone-based tents cannot be taped waterproof. These must be lubricated with silicone to make them 100% waterproof. With that said. Most of the water on the inside of the tent-fabric is a result of condensation where the inner tent is the solution for a dry and comfortable tent if you are not using a stove.