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No, you increase the load, not necessarily the volume. That is, you COULD increase the volume, or the weight, or both. I generally go for moderate volume when loading, but keeping it constant, while increasing the weight each week. I then go for low volume for the deload, and stick to the low volume while increasing the weight for the intensity phase.

An example might be to do this while loading for 4 weeks:

Mon-Squats 5x5, Rows 5x5
Wed-Bench 5x5, OHP 5x5
Fri-Squats 5x5, Chins 5x5

As you can see, the volume is moderate (10 sets per workout, 3 times a week) and the work is based purely around core lifts NOT done to failure (this enables us to squat twice a week in the volume phase). After 4 weeks of this, starting off light, increasing the weight each session, you will be at the brink of overtraining. That's the time to deload. We drop down to a lighter volume, keeping the weights the same as the 5x5, but drop down to 3 reps, and drop down to two sessions a week:

Mon-Squats 3x3, Rows 3x3
Thu-Bench 3x3, OHP 1x3, Chins 1x3

You then continue to increase the weights each week, giving you the intensity loading. Once you hit a wall on the intensity phase, you could test your maxes and then go back to the volume phase (or perhaps spend a week doing lighter assistance work if you need an additional deload). The rebound effect from the near-overtraining of the volume phase will multiply the gains you will get from the intensity phase.

So for example, taking the Monday squat session, you might do this:

Volume Phase:
Week 1 - 140kgx5x5 (this should feel easy)
Week 2 - 145kgx5x5
Week 3 - 150kgx5x5 (this will be where your previous 5x5 max was - usually the same as your 8RM)
Week 4 - 155kgx5x5 (this will push you just past your previous best)

Deload:
Week 5 - 155kgx3x3 (keep the weight the same but reduce the overall load and frequency for a deload)

Intensity Phase:
Week 6 - 160kgx3x3
Week 7 - 165kgx3x3
Week 8 - 170kgx3x3

You might then test your maxes, and then start again with the 5x5 with (say) 145-150kg in your first week.

This is dual factor training (incorporating loading, deloading and periodisation). It will give you extremely good strength gains, and if you're eating enough, the mass gains will be huge too. However, it is intended for intermediate-advanced trainees who already have a good strength base. MOST more junior lifters (I class these as people who cannot yet deadlift twice their bodyweight) would be better off on a low volume single factor program which will allow them to increase the weight each week. Extremely advanced trainees should be doing a conjugated periodisation program (such as WSB), as the heavy weights they will be lifting are likely NOT to allow them to do that much volume without killing themselves on week 1 of the volume phase.