Step 1: Cut the insulation
Note that you can cut XPS by scoring it about halfway, and snapping it.
Step 2: Cut dimple mat
The idea for this piece is to space the laptop off of the insulation board, with a ventilated air space underneath. Admittedly, you can use a laptop on a table or a bed without a problem, but I figure more cooling=better.
The dimple mat comes from a company called Cosella Dorken; another company that makes a similar product is System Platon. Unfortunately, you might have a hard time finding it--I have seen Platon at only a few Home Depots. It also comes in big rolls--way too much for the project.
A similar product that you might be able to use is Dri-Cor; I have definitely seen this at a lot of Home Depots--it is 2'x2' squares that you lay down on your basement floor, to create a warmer/dryer floor.
Step 3: Attach it together
Step 4: Done! (and notes)
Ideas for improvements:
- Non-skid material so the laptop doesn't slip off (hasn't proven to be necessary yet)
- Cloth cover, to improve user interface portion (sweat buildup, etc.)
- If you have one of those recalled Dells or Apples, you might consider adding a layer of 5/8" Type X Drywall (one hour fire rating). Or maybe Kevlar.