Building a lean-to / veranda - advice for a complete newbie

[Peter Smithson]

Hi,

I've not posted here before but it looks like a well established group so I 'm hoping I can get some help.

I've managed to avoid DIY most of my life but I can put a fence post in and replace a panel. I know how to use a saw and a drill and I can put up she lves. That's about it. So please use "baby talk" with me!

This video -

has inspired me to try and build a lean-to over the patio that is going to be laid for me n ext week. I've also got some text instructions on how this thing is made - So that's what I' m talking about.

My questions are related to the size of it. In the text instructions it ta lks about placing the supporting posts 8ft (2.4m) from the house. But my p lan involves putting the posts in the ground outside of the area of the pat io and the patio is going to end about 4m from the house.

Will I be able to get joists that are over 4m easily? Most things in B&Q s eem to go up to about 3m.

Will they be strong enough to support a persons weight when they are that l ong? I guess that depends on how far apart I put them.

Would a better option be to make the lean-to smaller than the patio?

Bonus question - I liked the idea shown near the start of the youtube video where the post is held above the concrete to keep it try and also, you cou ld replace the wood later without digging up the concrete. Is this a commo n idea? Is there something pre-made that I could use instead?

Any other tips welcome on things like rake of the roof and what might be be st to make the roof out of (polycarbonate transparent sheets or transparent corrugated sheets) and what size sheets. I'm also thinking that some acce ss to the gutters afterwards would be nice so perhaps some extra bit of woo d running the length of it that might somehow support a ladder.

Thanks.

Peter.

[Tim Watts]

4.8m is available - and longer may be possible.

I suspect 6x2" rafters would be wise over 4m. You have to allow for snow loading and the fact that at some point someone will want to climb on it to access the upstairs for maintenance.

Dave the Medway Handyman builds lots of decking and other garden timber projects - he'll be able to give better numbers than me.

Dunno - but yes, it is a very good idea.

It's likely to be noisy when it rains.

Or make a section easily removable so you can poke the ladder through it.

A lateral idea:

Build it without a covering (open frame) and grow some vines, climbers or some plants over it.

Add a pull out roller awning (like shops used to have) that pulls out under (or over) the whole thing.

One of our pubs did this. It's nice when it's open in summer with the plants providing shade. It looks nice. And the awning deals with the rain without the disadvantages of a polycarb roof. You'd be better off with a timber merchant who can deliver.

To do a price up, have a look here:

That will give you the standard sizes and prices. Timber merchants are notorious for fleecing the public so it's best to go prepared to negotiate.

[Capitol]

The building regulations gives the span and timber sizes for flat roofs, which is applicable IMO.

[David]

We have a covered deck which goes out about 2.4m. This is connected to a single storey extension which is about 2.6m. So in total about 5m.

Rafters are nominal 2*5 at 1m spacing (apologies for the Imperial/Metric mix) which is pushing the boundaries for the plastic twin-wall sheeting we are using. For rafters nearly twice as long you may well have to use larger timbers. There should be plenty of on line resources for calculating the rafter sizes for a given span and spacing.

Your biggest issue is going to be the slope on the roof - a lot of roofing systems specify a minimum fall (about 15 degrees if my failing memory serves me) and we went below this to get the tin roof and plastic roof at the same slope and still fitting under the upstairs windows.

So - first thing, measure the height from the bottom of your lowest upstairs window (or other item which needs to be above the flashing) and the height of the outer edge of your roof (you will probably need at least

2m clearance to avoid tall people banging their heads) from the bottom of the supporting cross piece.

%20Carport/DSC_0890.jpg

This should give you an idea of the finished result.

You should be able to see that we used powder coated steel for the uprights. The horizontal member which supports the joists is made up of

50mm * 8" nominal steel plate sandwiched between two 2 * 8 timbers.

This is a very strong support resting on the powder coated 4"/100mm square box section steels.

We sized it this way to give the maximum reasonable clear space across the deck, instead of having more regular, lighter uprights. The space between the uprights is about the same as our folding doors so you have an uninterrupted view of the garden.

I have loads of bits of information stashed away and will try and add more later.

For the joists, go to a builders' merchants in preference to B&Q - they deal with house construction and have bigger bits of timber.

As well as the roofing you will need a fixing system to hold the roofing in place - generally called glazing bars - assuming that you are using flat twin walled polycarbonate.

Corrugated plastic is easier to fix but to me seems a lot more tacky and flimsy. Then again I tend to over engineer.

Find a specialist supplier of roofing plastic and they should also have an advice service which can specify timber sizes and all appropriate fixings.

and

are two examples.

Cheers

Dave R

[Peter Smithson]

Thanks for some great info. I have saved the links too and will have a look later.

[Peter Smithson]

A friend suggested that but we have a very strange house. We just moved in and the washing machine and dryer are outside! They are in a big green pl astic box. We thought some permanent cover would be good so we can do laun dry in rain without getting wet. The wife also has a wicker hanging chair that she'd like to have out permanently. So looking for a permanent cover of some sort and this seemed to be cheapest way.

Cheers.