Pop up top - waterproof?

Mo! said:

HI everyone - Does the internal Cali Cozy prevent the 3 x upstairs LED lights on a 2016 T6 Ocean being utilised? I did email the shop but no response yet..... Thanks Mo!

Click to expand...

No problem at all, they are not obstructed in any way and operate as normal.

Great, thanks mate

The canvas is very well impregnated to be waterproof. The toppers will add isolation (because of the air trapped between the two walls) and for the same reason less condensation on the inside of the tent on colder days.

My roof is 10 years old and not very well preserved (right word for keeping something in good condition?) and probably never re-impregnated and still no drop entering the tent, even in heavy rain and strong winds.

Just returned from our first trip in SusiBus T6, and I must say found the new roof fabric vast improvement over the T5 fabric, much more waterproof, folds in better when closing, I like the fact that it lets more light through, because when you've got the roof up it helps with the light and airy atmosphere inside the van.
At last I can praise VW for what I consider an improvement!

Now back to roof corrosion!!!

Interesting. .. Can someone tell me how the zip windows would work with the internal topper please as we like to open them up in the mornings? Thanks Pete

petethebeat said:

Interesting. .. Can someone tell me how the zip windows would work with the internal topper please as we like to open them up in the mornings? Thanks Pete

Click to expand...

Iso-top has zipped windows larger than the pop top canvas exactly in line.

As I will be travelling to Spain in July for 6 weeks, the heat insulation is an important factor. So the question is which is the best Brandrup iso-top or Comfortz cosi ?

NI Bob said:

As I will be travelling to Spain in July for 6 weeks, the heat insulation is an important factor. So the question is which is the best Brandrup iso-top or Comfortz cosi ?

Click to expand...

Bob, the insulation benefits referred to above are in respect of retaining heat in winter, not shedding heat in summer. I'm not sure anyone is expecting that a topper would keep the van cooler in hot weather (IMO it would certainly not - it would impede convection of the warm air from inside the van and, given that most toppers are black or dark grey, it would actually absorb solar radiation not reflect it).

Or did I misunderstand your question?

Velma's Dad said:

Bob, the insulation benefits referred to above are in respect of retaining heat in winter, not shedding heat in summer. I'm not sure anyone is expecting that a topper would keep the van cooler in hot weather (IMO it would certainly not - it would impede convection of the warm air from inside the van and, given that most toppers are black or dark grey, it would actually absorb solar radiation not reflect it).

Or did I misunderstand your question?

Click to expand...

Hi Velma's Dad,
No you didn't misunderstand my question. The description specification on the isotop states that it will keep the the roof area cooler in summer due to the isolating air cushion (trapped air between the gaiter & the isotop). I can understand your point about the topper not shedding heat but in a hot climate its about shielding from the sun therefore my question stills stands, if anyone has had any practical experience of these internal liners making a marked difference to the temperature of the roof area in hot weather?

Actually when I fitted our SE with it's Brandrup Isotop it was a stinking hot day. The upper deck was very warm and rather unpleasant until the liner went in and this environment became noticably cooler. Since then we haven't had the chance to use it when the weathers been that hot.
We have used our van alot over the winter and the Isotop makes a big difference. It keeps the van much warmer.

I must say (and without actually having tried it!) that I'd be a bit dubious about claims that any topper keeps the van cooler in summer. Here is my rationale.

When the sun shines the body of the Cali, being a steel and glass box, will cause the inside the heat up - ie as any car on a hot day. The air temperature inside the van will be higher than the air outside (even if it 'feels' hotter outside due to direct radiation onto your skin).

Having the pop-up roof raised creates the conditions for some 'stack effect' cooling, ie the warmer air in the van has the chance to rise, and then exits through the roof canvas - especially if you have the bellows 'windows' open. This upwards airflow then allows cooler air to be drawn in from outside through the van side door and windows.

Impeding that airflow by putting a topper over the bellows would surely reduce this ventilation cooling process?

I take Bob's point about sun shielding. I see that a topper might reduce direct heating of the 'roof space' in situations where the sun is falling directly onto the side of the bellows. Especially if the topper is somewhat reflective, while also having 'windows' that align with the ones in the bellows.

Keeping the body of the van cool in daytime is a different requirement to keeping the 'upstairs' cool at night - although at night I'd still expect a topper of any kind to tend to retain the heat rather than allowing it to escape.

Note I am talking here about 'external' toppers. There might be somewhat different characteristics with an 'internal' topper (eg the Brandrup Isotop that Borris describes and Bob is considering).

It would be nice if it was hot enough to find out. Not much chance of that happening for a while.

Borris said:

It would be nice if it was hot enough to find out. Not much chance of that happening for a while.

Click to expand...

Just on our way to Scotland. Plan to be camping near Aviemore tomorrow night. Keeping the van cool seems not to be one of Mrs VD's concerns at the mo.

An internal liner probably makes it cooler upstairs merely by reducing radiated heat from the sun through the canvas bellows. The convected heat from the hot van would still rise internally though. At least with an internal liner you can also open the vents that mirror those in the canvas bellows. Even with both bellows and liner vents open the internal liner would probably still keep the upper deck cooler and therefore increase the convection efficiency. An external topper would just bottle it up like wearing a plastic mac in a heat wave.

I may be talking a total b*!!$ and it wouldn't be for the first time but as a theory it makes some sort of sense to me.

Thank you Velma's Dad and Borris both for your input. I have made the decision to go for an isotop, will be an expert on heat transfer when I arrive back in August, thermometer in hand

NI Bob said:

Thank you Velma's Dad and Borris both for your input. I have made the decision to go for an isotop, will be an expert on heat transfer when I arrive back in August, thermometer in hand

Click to expand...

Ours has just arrived! Will report back once fitted, though believe the ambient temperature for fitting needs to be 18 degrees or warmer - not much chance of that today!

See pic of our Cali with topper taken on a very cold Winter in Chester a few years ago