We have added the option to buy slim plinths to stand the Rainbow house sensory blocks 

They are freestanding, but to add more stability when lining them up in a row, you can slot them into these plinths to stand firmer 

Please note, due to the houses being approx 70cm long when lined up, we can't make one long plinth as it's not possible to send via normal post, so we have made two options 
 
1. Two halves which you can glue the open ends together to form one long plinth (using any white or clear craft glue)
2. Two complete plinths, but one to accomodate three houses and the other to fit the other four houses 

Better photos to follow 

Here's the houses 

Learning Aids, Resources, MDF Craft

Or search Sensory block rainbow houses