Use of an ash beam as a fireplace lintel?

[RJRock]

Hi all. I've a question that I'd like opinion on. See photos below for reference.

I want to insert a wood burner into my existing 1960's chimney breast. I removed an old rayburn rhapsody 401 and have cleaned out the whole space, not removed any bricks yet. (I've exposed a big void/gap on the right where back boiler pipes were).

The brest goes to ceiling height at 74" width, then narrows to 32" up to the roof. The brest is 32" deep.

There's a metal lintel 38" wide centered to the original opening and from the floor to its underside it's 30".

In a nutshell I want to insert an ash beam (6"x 6"x maximum width) at about 46" height and open up the underside, removing the existing metal lintel.

My questions are:
would an ash beam 6x6 be man enough?
what is the maximum width of beam I could use?
what would be the maximum opening width?
what have I missed?

Untitled

• RJRock
• 23 Jan 2013
• 1

Untitled

• RJRock
• 23 Jan 2013
• 1

Untitled

• RJRock
• 23 Jan 2013
• 1

 

[Norcon]

Whilst Ash is a fantastic strong timber I wouldn't use it as a supporting head.

I did one a while back and the first thing I did was thunder bolt a heavy channel iron section across the chimney breast. Then two small acrow props pushing up.

Then you can jack hammer away with confidence.
Then a concrete cast was formed in situ to form the head (which was re barred) and chimney liner support base all in a single pour.

 

[noseall]

Then a concrete cast was formed in situ to form the head (which was re barred)

Do people still faff about doing that or was this back in the '50s.

You can buy reinforced concrete lintels for a few quid.

 

[AronSearle]

I don't know anything about lintels so this may not help, but remember that a timber section that size will likely be air dried or green, so it will shrink in it's cross section by a few mm's as it dries (about 6% if green 3% if air dried).

 

[RJRock]

Whilst Ash is a fantastic strong timber I wouldn't use it as a supporting head.

I did one a while back and the first thing I did was thunder bolt a heavy channel iron section across the chimney breast. Then two small acrow props pushing up.

Then you can jack hammer away with confidence.
Then a concrete cast was formed in situ to form the head (which was re barred) and chimney liner support base all in a single pour.

Thanks for the advice Norcon. From what you are saying 6x6 ash beam (dried - thanks AronSearle), even though is strong, cannot be trusted, so I'd need to insert a lintel of sorts (thanks noseall) above? we are after the beam look and would like not to have to insert both.
What widths would you recommend, bearing in mind the measurements in my original post?

A thought - could I insert a lintel behind a wooden beam, leaving the beam exposed? Or is that pointless?

 

[Norcon]

Then a concrete cast was formed in situ to form the head (which was re barred)

Do people still faff about doing that or was this back in the '50s.

You can buy reinforced concrete lintels for a few quid.

I can make my own heads for less than a few quid if notion takes me.
Easy peasy. But on that particular job the pour completed all building works in one go.
You'd still be faffing around with your foolish building trowel.

Poured 130 ton of the wet stuff into peri shuttering this week. All cleared up and loaded today in the pouring rain, knee deep in mud ready for the next job.
Rain, snow or frost we never stop and we had it all this week. Were the paratroopers of the building trade. Not a pretty sight 10 feet below ground level this time of year inside an excavation hole.
What have you done all week?
Nice wee inside job nailing on a few skirtings?

 

[noseall]

What have you done all week?
Nice wee inside job nailing on a few skirtings?

Naff all.
Quoted a couple of jobs, moved a bit of gear. Too cold for bricklaying here in the mid's.

 

[dann09]

Norcon says it's "easy peasy" to make his own heads. Perhaps, as long as the conditions for pre-cast lintels are met:, ie. the mix and the curing times, pre-stressing and the location of the re-bar etc.

Sure, we all ocasionally cast them in-situ, (sometimes pre-cast as well) and it usually passes BCO and works. Come the day tho when multi-point loads apply, then cracks in the theory and the mud might appear.

AAMOI: Bootnecks always before Paras. Paras even claim to have brought sex into the world but Bootnecks gave it to women.

 

[RJRock]

AAMOI: Bootnecks always before Paras. Paras even claim to have brought sex into the world but Bootnecks gave it to women.

LOL. Don't forget those with green lids are part of the RN.