When using a notebook/laptop computer actually in your lap, the heat buildup can get annoying. This pad is meant to insulate you from the computer-generated heat, while still allowing it to dissipate heat from below.

Step 1: Cut the Insulation

I used extruded polystyrene (XPS) insulation board (the pink stuff; the blue stuff and green stuff are similar). I would not recommended expanded polystyrene (EPS) board--the white coffee cup foam--it tends to crumble when cut.

Note that you can cut XPS by scoring it about halfway, and snapping it.

Step 2: Cut Dimple Mat

I am in the building research field, so I have some of this plastic 'dimple mat' hanging around my lab. This product is typically used to waterproof foundations--it creates a drained air space, so that any water that gets in drains out.

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

I used rubber bands for this--I originally planned to glue it (using foam board safe construction adhesive/Liquid Nails), but the rubber bands seem to work well enough.

Step 4: Done! (and Notes)

This is what it should look like when done.

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.