John Brett

John is a professional engineer with 50 years experience.

John has designed and built many cars, trucks, and vehicle assembly facilities.

John has worked on design of roads, bridges, cranes, transmission towers, and buildings, and operation, maintenance and upgrade of hydro and gas turbine power stations.

John was a LVV Certifier for 13 years. John has long been a whistle-blower, expressing the view that the LVV system is dangerously deficient. John’s authority was revoked in December 2012.

John rides a 1992 Yamaha FJ1200ABS, and is also a keen road and off road cyclist.


“The LVVTA has brought it to my attention that statements I have made in relation to it and its employees may have been perceived as defamatory.

I sincerely regret that and apologise for any harm caused. I have taken down the statements identified by the LVVTA of concern to it.

I have strong views about the low volume vehicle certification process and intend in the future to direct my energies into the public inquiry now being held in relation to it.”

John Brett 7th October 2015


1. Disclaimer

The opinions, beliefs and viewpoints expressed by the various authors and forum participants on this web site do not necessarily reflect the opinions, beliefs and viewpoints of the owners of this website or official policies of the owners of this website

2. Copyright Statement and Policy

A. The author of each article published on this web site owns his or her own words.
B. The articles on this web site may be freely redistributed in other media and non-commercial publications as long as the following conditions are met.
(i)    The redistributed article may not be abridged, edited or altered in any way without the express consent of the author.
(ii)   The redistributed article may not be sold for a profit or included in another media or publication that is sold for a profit without the express consent of the author.
(iii)    The articles on this web site may be included in a commercial publication or other media only if prior consent for republication is received from the author. The author may request compensation for republication for commercial uses.

3. Submissions

An article may be submitted for possible publication on this web site in the following manner.

A. Logging in an Author
B. The website owners reserve the right to approve or decline Authors.
C. Articles are published on this web site only on the condition that the author agrees to the terms of the Copyright Statement and Policy above.

Motor Homes, Caravans

Most motor caravans and motorhomes need LVV Certification, or Heavy Vehicle Certification if the GVM is over 3500kg.

Hi-top Caravan

Hi-top Caravan

The Toyota Hiace pictured needs certification because it has had a roof-chop, and a fibreglass hi-top fitted. The Certifying Engineer has to be satisfied that the structural integrity of the vehicle is not compromised by the modification.

Caravan Seatbelt Anchorage

Caravan Seatbelt Anchorage

Seats and seatbelts- There needs to be a seat, and seatbelt for every sleeping berth in a motor-home. A typical Van chassis might have 4 berths, but only two front seasts. This means that two additional seating positions will have to be provided.

Side-facing lap-belts are legal, but not a good option, because of the poor protection that they provide. The picture above shows a typical Seatbelt Anchorage frame for two occupants with 3 point lap and diagonal belts. This structure is concealed by the caravan furnishings.

Note that rear facing seats also need to be able to restrain occupants in a frontal collision, so a suitable back and headrest is required.

Caravans heavier than 3500kg require Certification by a HV Engineer, and we can provide that Certification also.

By John Brett Technology Ltd ph 0800 LOWVOLUME (0800 569865)

29 comments to Motor Homes, Caravans

  • Danny Wilson

    Hi I have a motor home that has been modified then certified in 2003 … how do i go about having its GVM re checked if i think its not correct

    • johnbrett

      The first stop should be VTNZ, VINZ, or AA, at a proper testing station.
      You could email me the details and I could see what I could find out.

  • Danny Wilson

    Just had a COF done and the inspectors muttered somthing about the fact that the tandem wheel rear axel wa not standard to a 1988 dyna truck and it looked like the GVM was n the light side the tare weight is 3300kg and the GVM is 3550kg ? i have looked at similar trucks with a motor home coversion and the GVM is much higher ? what should i do

  • Danny Wilson

    Truck has a 100litre water tank plus my wife and i and we look over the limit … truck was turned into a motor home by a wellington boat builder and he did a great job … chassis has been lengthened by 900mm and its all certified and drives very well and is stable.. rego is DAM22

  • John Brett

    All the info you want will be on Landata, including the details of the Certification and the approved GVM. See my previous comment- get a Testing Station to access Landata and look at NOTES and IVCERT screens.


  • Danny Wilson

    yes did that and the figures are correct for that model Dyna truck LY60 but we are thinking that the rear axel is different ?…. heard that you are aok up to 5% over your GVM ? and that would give me another 176kg

  • Excellent post, couldn’t agree more. I found your post through Bing.

  • Gennaro

    Hi, I have a long wheel base ford transit I use as campervan. I was thinking of building a pop-top to gain some extra headroom. Where can I find some guidelines on what is required for this kind of modification?

    • johnbrett

      Are you planning a whole roof cutout, with a Fibreglass hi-top, or just a lifting section? The aim is to make sure that it will meet the requirments before you start. Best idea is to talk to a Certifier in your area. If you are in Auckland ring us on 0800 569865 Regards John

  • Gennaro

    It will be a lifting section, I’m up in Northland, I guess i can still give you guys a call…

  • Edwyn

    hiya, can anyone help me to find a fibreglass hi top for a 1998 nissan vannette (which they tell me is just a re badged mazda).i am in Waitakere….cheers

  • Laurian

    Hi John
    I am looking to convert a 1998 Honda Stepwagon – RF1 chassie in a small camper van. Among some other things I am looking to make a removable fibreglass roof canopy which I am planning to take off from the vehicle for the day to day use, so I can still park it in the garage.
    The car has already two sun roofs on the top, one of them reasonably large approx 500 x 700mm. This will give enough access for the kids to get up in a bed mounted in the roof top cavity. I do not intend to cut the vehicle roof, just to mount the fiberglass canopy on top of the existing roof by using the existing 3 points per side factory made roof rack mounting holes as fixing points.
    Is any certification required in this case as I am not doing any modifications to the vehicle other than virtually mounting a roof box?
    Please advise.
    Thanks & regards

    • johnbrett

      What a clever conversion! I agree with you that there does not seem to be any structural modification which would need Certification. The part you are adding would just be a “roof-rack”. Check the Honda ratings for roof-rack loads etc to be on the safe side. Regards


  • John

    I purchased a Ford Econovan Hitop 1992 an ex rental. Was warranted when purchased and got first warrant no problem. On trying for 2nd warrant told I need to have the fibreglass top certified. Is this correct and if so how do the rental companies get warrants without certification.
    Advice would be appreciated.

  • Derek

    Hi I have a Mitsubishi Rosa with a GVM of 6100, I have seen other Rosas and their GVM is 6000 which means it can be driven on a car licence, how do I reduce my GVM by 100.

    • johnbrett

      I’m sorry Derek, I don’t have any real knowledge on the subject. I believe that NZTA do have a system, a TSD agent such as VTNZ should be able to advise.

  • myke boots

    Hi .. I have a 1996 hi roof,super custom toyota hiace and im looking for a fibre glass roof top to convert and extend .. where could i find someone to make one .. or does someone know where i may find a ready made one .. and how much would something like this cost to certify? thanks Mike

    • johnbrett

      Hi Myke
      I know exactly what you mean, but can’t help. I can only suggest you see who is doing fibreglass these days, or even try one of the Caravan builders. As for Certification, there is a bit of a shortage now- I suggest you ask NZTA on their 0800 108 809

      Thanks for your query



  • shane larsen

    Hi I am just about to start re- building my chopper motorcycle frame to get legal as old frame was not up to standard
    It is a hardtail frame I am building
    1st question were do I start
    what welds have to be Cerf
    do I need to use seamless pipe

    • johnbrett

      Hi Shane
      If you are in Auckland, or nearby, the man you should speak to is Alex Gee, on 027 2647282. He will give you all the answers. I suggest you contact Alex first, to avoid doing things he might want you to change later.

      There is no charge for this free advice, but could I ask that you make a small donation to my ‘Give-a Little’ campaign? This is to cover legal costs for defending myself from Defamation charges made by Mr Johnson of the LVVTA.
      If you did want to, just click though to the Give-a Little page.



  • anthony

    ive got a ford transit custom (monocoque design) the im converting into a camper im wanting to drill holes in the floor the shower is the biggest at 80mm and the rest are 25mm.ill only be drilling through the floor skin no chassis rails or crossmembers will be touched do you think this will be alright or will it need a certifer to look at it

    • johnbrett

      Hi Anthony
      I know the Transit well, I helped put them into production at Ford Seaview, Those holes will not be any problem for a WOF. No Cert needed
      Cheers John

  • Megan Hieatt

    Hi John, I’m investigating a 4wd ute based camper build. If a camper is permanantly attached to the chassis, and the pass through from cab to camper is via removing the existing window with no alteration to the cab structure, is LVV certification or engineering input required? I am aware of tight payload and am looking at ute models where a legal GVM upgrade is available to take the payload to the maximum available, and as light a construction as possible. thanks, Megan

    • johnbrett

      Hi Megan
      What a great idea! I take it that this is not fitting into an existing tray, but replacing the tray.
      There is no structural alteration involved, so no Certification needed. The first WOF inspection will check body mountings, lights etc, and if satisfied issue a WOF. You will still need an Electrical Cert if you have mains power, a gas certificate, and a self containment inspection, (NOT WOF ITEMS) but not a LVV Certification.

      Good luck


  • William Howard

    Hi John

    I’ve been looking at an ex-hire campervan that was imported as a standard low roof Hiace van and then chopped and fitted with a fibreglass high top. Three roof bow braces were removed for the install.

    The van has LVV certification (from 2007) but has bowed outwards by 30mm on each side at the centre pillar (C pillar) at the rain gutter level. The deflection gradually decreases as the C pillar descends to meet the chassis.

    Inspection reveals that no additional strengthening has been built in to compensate for the removal of the roof panel and roof bows. To my eye, the structural integrity of the van has been compromised.

    In your opinion, does this work meet the requirements for LVV certification and if not, how should the vehicle have been strengthened and, should the owner wish to make a claim against someone, who is that someone (e.g. former owner, certifier, NZTA etc.)?


    • johnbrett

      Hi Willliam

      Sorry to take so long to reply
      The vehicle should already have a LVV Certification if it has been on the road in NZ
      Look for the Cert plate, or ask the Low Volume Vehicle Technical Association if it is certified, and about the safety of the vehicle



  • Murray


    Im building a 2005 Ford transit lwb xtrahigh roof camper,ive seen its ok to put a roof vent in the roof and i beleive side windows are ok if only going through non stressed single layer of panel steel and not within 150mm of seat belt anchorage. Anyway as much as ive searched i put a service hatch into the side of the vehicle for the toilet cassette to pass through,single layer only and no supports cut into and over 150mm to seat belt fixing,is a service hatch classed as a window or does it need certification thanks

    • johnbrett

      Hi Murray-
      I don’t believe that any LVV Certification is needed for this. It might pay for you to check with your local WOF agent- it is their responsibility to make the decision.


Leave a Reply

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>