Converting 2 single garage doors to 1 double?

[LionelR]

Hi all,

We're thinking about converting our 2 single garage doors to 1 double door by removing the brickwork separating the two doors. This brickwork is about 10" wide x 12" deep and looks like it might be supporting the wooden lintel going across the entire width of the garage. The lintel itself is approx. 10" x 10" in section, 16' long with 6" at each end embedded in the side walls.

Firstly, is it likely that the brickwork between the 2 doors is load-bearing? Would removing this mean that we needed to replace the wooden lintel with a steel RSJ, or is there some other way of strengthening the wood lintel? Assuming we had to replace it with a steel RSJ, is this something a that can be done by a reasonably competent DIY-er but with no previous building experience, or one left for the pros? Finally, roughly how much would it cost to have this work done (ballpark figure)?

Many thanks and apologies if I'm using all the wrong terminology.

 

[masona]

Just done one couple of week ago, I removed the brickwork & 2 lintel above the the garage door, then made timber studwork above the new double door frame to pick up the upvc cladding. I don't know how competent diy you are but taking it down is the easiest part providing you have check the load pressure is okay, I made a temporary studding inside the garage to hold the roof up but it did held up on it own but better be safe then sorry. The important is that the frame must be plumb and square otherwise headache for the garage door. If you not confident with the door maybe get a quote just for the garage door. Can't give you a ballpark figure as every garages are difference.

 

[mrscalex]

What's above your garage? What are the lintels holding up? They must be holding something up otherwise you wouldn't need them! It might be a second storey or the roof!

I only have the experience of removing an internal load bearing wall to go on (which I didn't do myself) but this needed the services of a structural engineer to calculate the RSJ size and Building Control to oversee and sign the work off. And of course you've got to prop the load while you do it. But that's only if it's load bearing.

The lintels on my garages do no more than support a soldier course of engineering bricks.

If in doubt a structural engineer will probably cost about £250 to make a report but it might prove money well spent. Even if it's just to accompany a house sale to keep a prospective purchaser happy when their surveyor sees that work's been done.

 

[LionelR]

Thanks for the replies!

masona: I guess you're suggesting that I will need to replace the wood joist with an RSJ?

mrscalex: the existing lintel is supporting horizontal and sloping joists which form the garage roof. I would plan on supporting the horizontal beams using steel props whilst the lintel is replaced with an RSJ.

My main question is whether I can get away with leaving the existing wood joist in place when removing the brickwork separating the 2 single doors, ie. will the current wood joist collapse or sag in the middle over time?

Thanks in advance.

 

[masona]

Any photo?

 

[LionelR]

I'll take a couple this evening and post them up, cheers.

 

[LionelR]

I've sent a few pictures to the DIYNot administrators who will hopefully post them up for me shortly.

Thanks in advance!

 

[LionelR]

Just uploaded a few pics here:

http://community.webshots.com/album/389543139qvrqqH

 

[masona]

Is the joist in one length and not join at the centre pier?

What is the size of the joist? Is it a double joist bolted together?

 

[LionelR]

The joist is 1 continuous piece, and not joined in the middle. From what I can tell it is not 2 joists bonded together. It's approx 16 foot long, and about 10" x 10" cross-section.

 

[pervader]

Well here's a response from your strawberry blond mate!!

Because of the span, you may end up with a hefty size RSJ unless some calcs are done to size for the minimum. If you get the calcs done professionally though, this can cost almost as much (if not more) than upsizing the RSJ for a good safety factor.
As a cheap DIY option an an alternative to installing an RSJ, you might consider the following if you feel competant.
If you can acquire steel plates (possibly 10-15mm thick, depth of joist and as long as possible) or better still angle iron (right angled steel sections), you might be able to bolt these into the existing lintel to provide additional stiffness. Either overlap the main plates or use “Fishplates” and build the length up to span the whole beam in as few plates as possible. In effect this becomes a mocked up RSJ.
Steel plates will be quite cheap – probably 50 quid or so – angle irons a little more expensive. A good size drill should be able to go through these (with application of cutting fluid) (or get the local yard to predrill them with a pillar drill – probably another 50 quid), and screwed into the existing beam which had been predrilled with pilot holes using decent size wood screws, say 8mm or 10mm.
Can be done with beam in-situ so avoids the need to use acroprops to support the existing garage roof, but I might want to use one as you knock out the central pillar to be safe, then unwind it gradually and note any sag (hopefully none).
Rough calcs would need to be done to assess
a) static roof loads
b) dynamic roof loads (for snow etc.)
c) confirm bearing capacity of brickwork supports
d) then calculate thickness of plate / angle
e) then calculate screw size, spacing etc.
The calcs are simple stuff for a structural engineer, taking about an hour, but might cost 80 quid if you can explain/sketch/photo the problem without him needing a site visit.
A professional job on the other hand would probably take a two-man building team less than a day (charges at 500 quid including equipment) and then the cost of the RSJ (depends on size)? Even so, I would recommend someone with knowledge to size the RSJ and check the supporting padstones/brickwork is adequate. Builders tend to do this by eye in the absence of any calcs, which is OK if you have a experienced builder but watch out for the cowboys!!

The Building Control officer from the council might take an interest (in order to be properly legally compliant); besides, some BC officers can be very helpful. His consultation should be free unless your asking for him to do some sort of inspection. His involvement may not extend to more than asking what size beam you’re using and who your builder is, although he might want a site visit to get out the office on these sunny days, and may ask to see calcs if he’s not too busy!

 

[wkt20]

I also want to convert my garage from 2 doors to 1 double door. However, my garage is supported by 2 separate lintels. I would really appreciate some advice on this matter: I would hope that the company that supply and fit the garage door can replace the 2 lintels with one longer one. Can anyone suggest a company that does all these jobs in Leicestershire area? How much would the whole project cost:

1) to knock down the centre pillar
2) to replace the two separate lintels with a single piece lintel
3) to supply and fit a double door
4) to supply and fit an electric garage door opener

Is it going to be £1000? £2000 or more?

 

[LionelR]

Hi, as a guide this is roughly what I paid in the end:

1) & 2) £700 (used a local builder to replace the wood lintels with a single RSJ, included re-routing drainage)
Supplying 3) & 4) £550 delivered (new Garador opener and new Henderson 15' door kit, both from eBay - bargain!)
Fitting 3) & 4) £325 from http://www.garagedoors-sw.co.uk/ which included fitting a new wood frame

If you looking at full prices you could quite easily pay in excess of £1000 just for a new std. 14' garage door...

 

[wkt20]

Hi, as a guide this is roughly what I paid in the end:

1) & 2) £700 (used a local builder to replace the wood lintels with a single RSJ, included re-routing drainage)
Supplying 3) & 4) £550 delivered (new Garador opener and new Henderson 15' door kit, both from eBay - bargain!)
Fitting 3) & 4) £325 from http://www.garagedoors-sw.co.uk/ which included fitting a new wood frame

If you looking at full prices you could quite easily pay in excess of £1000 just for a new std. 14' garage door...

Thanks LionelR, what size of double door did you get? Did your double door cover the garage opening after the central pillar is removed?

 

[LionelR]

Hi, I went for a 15' wide (6 1/2' tall from memory?) garage door which fully covered the garage opening once the timber frame was installed by garagedoors-sw. The frame had to be planed slightly to fit but otherwise it was pretty much a perfect fit. They provide a choice of different sections of timber frame so you have a couple of inches of lee-way either way.