Chair mats can be a good idea for the office as long as you follow some simple guidelines.
The Problem
Office Chair Casters
There is little doubt office chair casters can do a lot of damage to floor coverings, particularly where the wrong casters are fitted.
Broadly speaking office chair casters are designed for either carpeted or hard flooring surfaces, so before doing anything check your office seat is fitted with the correct casters for your floor covering.
Even when the correct wheels are fitted, they can still do a lot of damage to floor coverings, this may be minimal with good quality carpet tiles and a serious problem with foam backed carpets as the wheels have the effect of shredding the foam backing over time.
You'll know when this is happening as the carpet will become uneven and may develop ridges and show signs of early wear.
So, you've got the correct casters on your chair and perhaps are still concerned about the marks left by your chair and decide to fit a chair mat, will this sort things?
Making The Best Use Of Chair Mats
Chair mats act as a barrier between the casters and your floor covering and will indeed protect your flooring from wheel damage.
This can actually throw up a fresh problem because when the mat is left in place what happens in time is the surrounding flooring will begin to wear with use, yet the mat will prevent wear to the flooring underneath it.
Consequently, you may end up with a situation where you reverse the problem you originally had where the protected flooring shows little or no signs of wear and so stands out against the rest of the carpeting.
To minimise this problem it's best to always lift the mat each time you vacuum your carpets and clean it as well, this will also raise the carpet pile too reducing the likelihood of the pile becoming flattened by continual use of a mat.
Where possible, try and move your workstation and chair around from time to time so you are working on different parts of the carpet as this will help even out wear and tear on your flooring.
Conclusion
Here's a summary of the points to check when considering chair mats.
Make sure you chair has the correct casters
Move and clean under the mat to revitalise the carpet pile
Where possible, try moving your workstation occasionally to even carpet wear