Hollow core vs solid core internal doors

A hollow core door has a honeycomb (cellular) core inside a timber frame, while a solid core door is filled with particle board, MDF or solid pine. In the range a standard honeycomb door weighs about 14kg and is rated Rw 25, while solid cores weigh roughly 30 to 45kg and rate Rw 29 to 30. Choose hollow core for wardrobes and low-traffic rooms, and solid core where sound control and durability matter.

What is the difference between hollow core and solid core?

Most flush and panel doors are built the same basic way: a frame of stiles and rails around a core, with a face material (the skin) on each side. The core is what changes.

• Hollow core doors use a honeycomb or cellular core. A lock block of particle board or MDF sits inside the door to give the handle and latch a secure fixing point, and an extra lock block can be ordered for honeycomb flush doors.
• Solid core doors are filled throughout, with a moisture resistant particle and flax board core (Solicore), a moisture resistant MDF core (HMR MDF) or a solid timber pine blockboard core (STPC).

How do the manufacturer's door cores compare?

Weights are the manufacturer's estimates for a 2040 x 820mm door, 35mm thick unless noted.

Construction	Core	Rw / STC	Est. weight	Found in
Honeycomb (H1) hollow core	Cellular honeycomb with lock block	25 / 25	14kg	Accent, Strata, Moulded Panel, H1 flush doors
Honeycomb (X1) hollow core	Cellular honeycomb, the manufacturer's external honeycomb option	25 / 25	14kg (40mm)	X1 flush doors, Glass Opening XF1 and XF3
Premium 6mm (SG) hollow core	Maximum density cellular core, 6mm skin	27 / 27	18kg	Sorrento, Linear Internal, Accent Premium
Hampton construction	Solid infill, pre-primed face	25 / 25 (Luxe)	14kg (Luxe), 20kg (Hampton)	Hampton, Luxe
HMR MDF (HV) solid core	Moisture resistant MDF	29 / 29	30kg	Bayview, Allure, Humecraft
Solicore (SCX1)	Moisture resistant particle/flax board in a timber frame	29 / 29 (35mm), 30 / 29 (40mm)	30kg (35mm), 45kg (40mm)	SCX1 flush doors, solid Accent and Moulded Panel
Blockboard (STPC) solid core	Solid timber pine blockboard	29 / 29 (35mm), 30 / 29 (40mm)	35kg (40mm)	STPC flush doors

How much quieter is a solid core door?

Rw and STC ratings indicate how many decibels a door reduces sound by. The manufacturer's sound guide describes the difference roughly like this:

• Rw 25 (honeycomb): soft speech can be heard and understood through the door, and normal speech heard quite easily.
• Rw 27 (Premium 6mm): soft speech can be heard but not understood.
• Rw 29 to 30 (solid cores): soft speech cannot be heard or understood, and normal speech can be heard but not understood.

Those ratings depend on the door being installed with seals of an equivalent Rw/STC value, fitted to the seal manufacturer's recommendations.

Which core suits which room?

• Wardrobes, pantries and low-traffic rooms: The manufacturer describes honeycomb H1 doors as lightweight, budget-friendly and easy to install, suited to low-traffic areas such as wardrobe and pantry doors.
• Rooms where noise matters: The manufacturer recommends Solicore for sound-sensitive areas, and the HMR MDF ranges (Humecraft, Bayview and Allure) carry the same Rw 29 rating.
• Back doors and garage access: The manufacturer lists Solicore SCX1, Premium 6mm (SG) and X1 honeycomb doors for these, with X1 only where exposure and safety are not a concern. Solicore's Primecoat MDF face is for internal use only, so choose DuraXP, Paint Grade Ply, SPM or Tassie Oak.
• Odd-sized openings: Blockboard STPC can be cut to any shape or size. It is not recommended for exposed situations, every surface must be sealed or the guarantee is void, and the core can show through paint, so the manufacturer recommends Solicore for a superior paint finish.

Any door used externally should be hung in a weather protected area and sealed on all surfaces, as explained in our guide to caring for timber doors.

Does door weight matter?

Yes, for hardware. The manufacturer's guarantee requires three hinges on solid doors up to 2040 x 820mm and four (or a pivot system) on larger ones, while 2040mm hollow core Prehung doors come with two. For sliding doors, Evolution cavity units take doors up to 70kg and are recommended for 35mm doors only, but the add-on soft closer is rated to a 35kg door, so check the door weight if you want soft closing. Our guide on how to measure for a new door covers sizes and hinge positions.