Ridge shift — what is it and when should you do it?

What exactly is a ridge shift?

With a traditional saddle roof, the ridge is in the middle. With a 'ridge shift', you structurally move that ridge to the back (usually). The front roof retains its slope and appears largely unchanged from the street. The rear roof becomes steeper — almost vertical — which creates more height across the entire interior space.

Other terms: asymmetrical ridge raising, one-sided ridge raising, sometimes also called an 'attic pent roof'. Technically, it falls into the same category as a ridge raising, but the execution and impact are different.

Why choose a ridge shift?

• More aesthetic review (welstand) friendly: the front roof and street line remain the same. In 1930s neighbourhoods with intact rooflines, this increases the chance of receiving planning permission.
• Cheaper: less roof surface to renew (only rear), less scaffolding at the front. Saves 10–20 % compared to a full ridge raising.
• Considerable space gain: because the rear roof goes up almost vertically, you get full standing height over a large part of the loft.
• Good location for skylights or a dormer: the new rear roof offers ample opportunities for natural light.

Disadvantages and points of attention

• The feel of the interior space is asymmetrical — humans adapt quickly, but some people feel it is 'crooked'.
• The rear facade becomes visually heavier. From the garden, the house looks more square — some neighbourhoods do not appreciate that.
• Connection with neighbours can look messy if you shift the ridge and your neighbours do not.
• With continuous terraced houses, the connection requires extra attention for fire resistance and water drainage.
• The structure at the rear is steeper and bears more wind and rain load; a structural engineer must calculate this properly.

Ridge shift vs straight ridge raising

Both solutions create more standing height in the loft, but they differ:

• Straight ridge raising = ridge straight up, entire roof goes higher. Maximum space gain, also at the front, but the street view visibly changes.
• Ridge shift = ridge shifted sideways. Less space at the front, front facade unchanged, often cheaper and approved more quickly.

For those who want the maximum: a straight ridge raising. For those seeking a compromise between space, price, and aesthetic review: a ridge shift.

Practical: when to apply?

A ridge shift works best for:

• Terraced houses and 1930s homes with strongly defining street facades.
• Situations where aesthetic review is critical.
• Budgets between € 22.000 and € 35.000 (slightly below a straight ridge raising).
• Plans where the rear side facing the garden/backyard is less visually sensitive.
• Combination with a skylight or small dormer in the new rear roof.

Not ideal for:

• Detached homes where a regular ridge raising is possible anyway.
• Homes where you truly want full standing height on both sides.

Frequently asked questions

Short, honest answers to frequently asked questions.

Is a ridge shift permit-free?

No. Just like with a straight ridge raising, you are altering the main shape of the roof. An environmental planning permit (omgevingsvergunning) for construction activities is always required.

How much cheaper is it?

Expect a 10–20 % discount compared to a full ridge raising on the same house. The difference is mainly in the scaffolding and the front roof surface.

Can this also be shifted forward?

Technically yes, but aesthetic review (welstand) almost never approves it. By default, you shift it to the rear.

Will I get full standing height?

At the rear, yes, almost immediately from the rear facade. At the front, you keep a small sloped wall because the front roof remains unchanged.

What will my contractor say if I ask for a 'ridge shift'?

They will probably immediately understand. Some contractors call it an 'asymmetrical ridge raising' or 'rear roof extension'.

Is it the same as a roof extension?

No. A roof extension (dakopbouw) is a complete extra straight floor. A ridge shift remains a pitched roof, just with the ridge no longer in the middle.

Is this allowed in a protected cityscape?

Rarely — the roofline at the rear is also assessed. Ask the monuments committee of your municipality.

Summary

A ridge shift is an asymmetrical variant of a ridge raising: the ridge shifts sideways (usually to the rear), so that the front roof remains unchanged and the rear goes up more steeply. It yields a lot of space with less impact on the street view and is 10–20 % cheaper. For 1930s homes with strict aesthetic reviews (welstand), this is often the best compromise.