Caravans on block - safe?

[Hilldes]

We now have our static caravans in place and services connected. In order to get the fall for the foul drainage, we've had to raise the vans on stacks of dry laid concrete blocks. I'm a bit concerned about the height of the 'stilts' needed and the potential for the vans to be blown off in string winds (although we are in a relatively sheltered location). Options are:

 

• Leave as is
• beef up the blocks
• Lower vans and add pumping station (not too keen on this as circa £1K)

 

Here are some pics...

[PeterW]

Couple of screw in ground anchors and ratchet straps will stop it moving. 
 

Would also be worth getting some OSB framing around the base of the vans to stop the wind blowing under them as the insulation in the floor is negligible. 

[joe90]

4 minutes ago, PeterW said:

 

Would also be worth getting some OSB framing around the base of the vans to stop the wind blowing under them as the insulation in the floor is negligible. 

+1,

[Russell griffiths]

How far are you from the drain, that’s a lot of fall. 

[ProDave]

You have actually not lifted them very much.  Ours was jacked up so the wheels were only just off the ground and that defined the height. you don't look to be much more than 6" higher than that.

 

One observation, your first jacking point should be under the axle, you jack that up first and then get support under the axle and get it level across the van, everything else works out from that.  It seems you have no support under the axle with your first support in front of it? Apart from anything else this first support point only needs a very low stack of blocks and so is very stable.

 

Then there should be marks on the chassis showing the approved support points and those should be where your blocks go, on mine it is supported by a total of 12 pillars including the 2 under the axle.

 

Then as already mentioned some ground anchors and strap it down and it is going nowhere.

[Hilldes]

33 minutes ago, Russell griffiths said:

How far are you from the drain, that’s a lot of fall. 

@Russell griffiths total run of foul drain pipe to the vans is 28m. Laid at min 1:80 fall. Not helped by the fact that the existing drains I’m connecting into are shallow (about 400mm below ground level see y junction in this new pic) and also the lawn at the back where the vans are slopes downhill slighty.

[Hilldes]

3 hours ago, ProDave said:

You have actually not lifted them very much.  Ours was jacked up so the wheels were only just off the ground and that defined the height. you don't look to be much more than 6" higher than that.

 

One observation, your first jacking point should be under the axle, you jack that up first and then get support under the axle and get it level across the van, everything else works out from that.  It seems you have no support under the axle with your first support in front of it? Apart from anything else this first support point only needs a very low stack of blocks and so is very stable.

 

Then there should be marks on the chassis showing the approved support points and those should be where your blocks go, on mine it is supported by a total of 12 pillars including the 2 under the axle.

 

Then as already mentioned some ground anchors and strap it down and it is going nowhere.

 Thanks @ProDave you are right the wheels are only raised by about 30cm. The photo I took was from the high end of the vans where the lawn slopes and there are more blocks (and further to fall). Have used marked the jacking and support points either side of the axle for jacking, will add more blocks as we only have 6 piers per van at present and there are marked support points that don't have any.

 

I remember a picture from a holiday park after a gale/storm a few years back where static carvans had been tossed around like toys, which is what is making me a bit uneasy.

[Russell griffiths]

And they have a habit of floating off in a flood 

 

 

[epsilonGreedy]

500mm to 600mm off the ground is normal and your block stacks are 600 to 800 but they are double width.

 

I think it more likely that your wood sheet stack bases will rot over time and sag a bit. After some ground settlement I experienced the top wooden blocks blowing out of position in a gale and this provoked a disconcerting minor wobble. Keep an eye out for signs of stack settlement over the next few months and be prepared retrim the level to maintain a consistent weigh on the stacks, you might have 3/4 of a ton on each stack.

[Hilldes]

1 hour ago, epsilonGreedy said:

500mm to 600mm off the ground is normal and your block stacks are 600 to 800 but they are double width.

 

I think it more likely that your wood sheet stack bases will rot over time and sag a bit. After some ground settlement I experienced the top wooden blocks blowing out of position in a gale and this provoked a disconcerting minor wobble. Keep an eye out for signs of stack settlement over the next few months and be prepared retrim the level to maintain a consistent weigh on the stacks, you might have 3/4 of a ton on each stack.

Thanks @epsilonGreedy good to know this is not excessively high. I’ll be keeping a very close eye on the stacks and the the 18mm ply at the bases.

The weight per stack sounds about right - I think the empty 12x36 vans are 5 tons. SWMBO and the kids I think have added another ton or two already ?

 

Edited November 28, 2020 by Hilldes

[Hilldes]

11 hours ago, PeterW said:

Couple of screw in ground anchors and ratchet straps will stop it moving. 

@PeterW something like this....

 

https://www.leachs.com/scaffold-fixings-anchor-testing/big-ben-heavy-duty-hurricane-ground-anchor-choose-your-length?code=AF-6300-900&gclid=EAIaIQobChMIwZ3arpCm7QIV2PhRCh3USQUNEAQYASABEgKq0PD_BwE

[Hilldes]

4 hours ago, Russell griffiths said:

And they have a habit of floating off in a flood 

 

 

@Russell griffithsWe are in a technically in a flood zone ?‍♂️.

[joe90]

13 minutes ago, Hilldes said:

@Russell griffithsWe are in a technically in a flood zone ?‍♂️.

Then make your stacks even higher ??????

[PeterW]

25 minutes ago, Hilldes said:

@PeterW something like this....

 

https://www.leachs.com/scaffold-fixings-anchor-testing/big-ben-heavy-duty-hurricane-ground-anchor-choose-your-length?code=AF-6300-900&gclid=EAIaIQobChMIwZ3arpCm7QIV2PhRCh3USQUNEAQYASABEgKq0PD_BwE

Yep they are the ones !!

[Hilldes]

22 minutes ago, joe90 said:

Then make your stacks even higher ??????

https://www.shutterstock.com/image-photo/noahs-ark-construction-186687086 ?

[Bitpipe]

I remember the first night we spent in our van, was blowing a hooley - didn't get a wink of sleep as was terrified the van was going to flip over. Needless to say, it didn't and we 'enjoyed' 18 months in it.

 

Quick tip - use a dehumidifier over winter to keep the interior from getting damp - LPG hobs & fires emit a lot of water vapour which condenses out and feel cold in the morning.

 

You'll know if your van is getting out of level due to sagging props as the UPVC doors will start to bind and won't open easily,

[epsilonGreedy]

On 29/11/2020 at 08:17, Bitpipe said:

I You'll know if your van is getting out of level due to sagging props as the UPVC doors will start to bind and won't open easily,

 

 

Yes a static caravan is a floppy structure that can twist and distort quite a bit as it settles on its stacks. We self builders tend to abuse them by positioning them on soft ground whereas the holiday parks lay proper foundations for each site.

 

After 6 months I added an OSB skirt based on 2" by 2" wooden frame which supports some of the overall weight of the van. This has made the whole structure rock solid in high winds though others should consider if their static should have any support under the outside perimeter.

Edited November 30, 2020 by epsilonGreedy

[StevieD]

One thing you may want to consider is rainwater run off and SW drainage. We have been in our cabin for a year and during wet periods areas that don't have a great run off can really lead to saturated ground in patches - especially in areas where there is regular pedestrian/vehicle route. if you can direct the rainwater away into a watercourse or natural drainage point, great. Keeping a well drained area will help with settlement. 

 

i would also strongly consider adding an extra layer of insulation to the underside of the caravan and adding skirting around it. Caravans can get very drafty. Dehumidifier is a must too, we have them every other day in each room. 

 

Depending on how your cabin is situated, you may want to consider having a wind breaker for the S - SW winds. i.e. Site storage container or wind breaker on the Heras fencing (reinforce the fencing with supports/sandbags/etc.) - they have a habit of falling over in moderate winds at the best of times. 

[Hilldes]

Just installed a ground anchor. I bought only one as I was not sure they would work with our soil - it is littered with flint and other stones (when digging you are absolutely guaranteed to hit one with every entry of the shovel).On the 5th attempt, the ground anchor found a route through the stones and feels very firm (allegedly can handle 1.2 tons with the 900mm version I bought). I could fell it hitting stones, but I think it pushed them aside. Will now buy 3 more and the ratchet straps to tie the vans down. Will cost £250 in total but a small price to pay for peace of mind.