Questions and Answers

Ever seen wavy lines on a door? Have you seen gaps between the door and the door stops. Often with light shining through at night.

This is because a door is much like Plywood. The strength or structure of a door is based on a number of factors.

The Timber outer, the skin and the core. The most commonly used Hollowcore Doors in NZ are similar to using a low cost 7mm ply. 

Timber moves, so the outer frame needs counter elements to lessen the opportunity. 

When we use a Hollowcore we use a 4.75mm skin as a minimum. This lessens the chance greatly of doors changing shape.

RIbcore: Ribbed Polystyrene Core.

EPS: High Density Solid Core Polystyrene

Ribcore is the direct replacement to Honeycomb Core Doors.  With a Ribbed Polystyrene Core it gives about a 42% glue adhesion to the skin of the door (compared to Honeycomb at about 4%).

While the skin is generally only 3mm, with the polystyrene completely filling the void and then glued to the skin, it creates not only an all around structurally stronger door, but also better heat and noise insulation.

If you specifically want a high quality door at a reasonable price, the EPS door is the best option.

Used by Kainga Ora, (Housing New Zealand) these doors have a High Density Solid Polystyrene Core. Making them extremely difficult to damage. They come with a minimum of 4mm skin and a glue ratio of around 95%.

Heat and Noise insulation on these are extremely good, great for minimising heat loss, or reducing the noise from outside influences.

If we could, we would place these doors in every property. They are that good.

Great for Rentals, or larger scale developments.

RIbcore: Ribbed Polystyrene Core.

EPS: High Density Solid Core Polystyrene

The skin is the face of the door, the part that you see when the door is shut. The most common size skin is 3mm thick.

This is the part that receives the most paint. It is also the part that will flex when pushed and show imperfections. This is why we use Ribcore or EPS Doors as the void between both skins is fairly solid so the chance to flex or bow is minimised greatly. 

When we do use a Hollowcore Door, to greatly reduce the risk of flexing, we use a 4.75mm skin as a minimum. 

New Zealand, as do most countries, have standard door sizes. While they vary around the world, we are fortunae here as we have more options than most.This is based on the door manufacturers ability to mass produce.

If you need a door that is not a standard size, the door will need to be specially made to order. This increases not only the price quite dramatically but also the time frame to produce. A further cost to consider is that when being made into a Pre Hung door, again you are using a non standard size, requiring special jigs to be set up, as well as different measurements.

We have four standard heights. 1980mm (the most common), 2200mm, 2400mm and 2700mm.

There are 11 standard door widths, 410mm, 460mm, 510mm, 560mm, 610mm, 660mm, 710mm, 760mm, 810mm, 860mm, 910mm

Generally yes. A Plain Standard door, should be held in stock at the door manufacturer. However, the 2400 and 2700 are commonly made to order.

Designer Series Doors are cut out from the Standard Plain Doors. So in most cases, the door is already available, it is just a case of the manufacturer cutting out the design on their machines.

That will depend on the door style and size, but the range can be from 4-8 weeks. In some cases this can reduce based on availability of doors and factory cycles.

Before the plans go to the prenail factory. This enables us to talk to your factory and ensure that the trim sizing the manufacture to is correct. This save both time and money when it comes to install the doors.

If you are going to have hold ups on your build, it will be at the door stage most times. This is because pre hung doors are made to fit a defined space. It is generally very difficult to change on site. 

The reason being is that there are three different elements involved in Pre Hung Doors, the Architect, the Prenail Factory and the Pre Hung Door company. If there are any errors on the Architects design (which is very common) you end up having three different groups seeing three different perspectives. Worst of all, you don't know until the doors are ready for install.

We talk to the prenail factory prior to the Frame being Designed. We check their plan to check the Pre Nail is correct to the Trims required for the doors. We would already have talked to the Architect or customer prior to pricing, so we would be sure that all parties are seeing the same end product.

On occasion, yes, there would be a number of different reasons, but in most cases, they are not required.

Yes, in the industry the are called Door Leafs. We often get asked for them, especially unusual sizes or designs. We are happy to accomodate.

We have a strong relationship with a Nationwide Freight Company. To reduce costs, they will deliver to you local Trade Merchant (you will need to discuss with your specified merchant) or you can pick up from the freight depot.

Our Door System is unique and we are able to Flat Pack. Generally a houselot fits on a single Pallet and can be moved with a Trailer.

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You can email us at sales@prehung.co.nz, call us on 0800 400 790, or click the Lets Chat box and ask there.

We are seeking more questions for this section, so welcome your input.

Thank you