lime mortar

[richardmm]

hello everyone could someone explain me what is lime mortar and where it is used i think lime mortar is weak so why is istill available in shop? today i went b&q and i see it and the worker asked me which mix i want i didnt know if lime mortar would be suitable but i hear it is historic so why there? thank you guys

 

[noseall]

hello everyone could someone explain me what is lime mortar and where it is used i think lime mortar is weak so why is istill available in shop? today i went b&q and i see it and the worker asked me which mix i want i didnt know if lime mortar would be suitable but i hear it is historic so why there? thank you guys

Lime mortar is rarely used in modern builds.

 

[Heversham]

Right then. Lime mortar is what most houses were built with until before WW2. It has been entirely replaced in modern construction with cement-based mortars.

It is used as a mortar in wall construction, when the wall is made from brick or stone. It is also used as render for buildings made from timber, brick, stone or cob (and probably some others.)

It is a mix of lime putty and sand. It is weaker than cement, which is a good thing when you're using it on brick and stone as cement can damage a weaker substrate. It is also breathable. Lime tends to let a little moisture in but crucially allows it to escape again. Used properly it's the best thing for old houses, as it's more flexible than cement, breathable and softer than the walls it's used on.

But you won't get it in B&Q.

 

[stuart45]

hello everyone could someone explain me what is lime mortar and where it is used i think lime mortar is weak so why is istill available in shop? today i went b&q and i see it and the worker asked me which mix i want i didnt know if lime mortar would be suitable but i hear it is historic so why there? thank you guys

Lime mortar is a mix of lime and sand. There's many different types of sand, and many different types of lime. The 2 main types of lime are air limes, and hydraulic lime.

 

[richardmm]

thank u and why does chimney need ventilation as I will block it up in tomorrow and do I need ventilation for air brick?

The chimney in top on roof is opened and no one close it

 

[Heversham]

Air needs to flow through a chimney - you need a hole at the top and the bottom to create a draw, like a fire needs. You need an air brick or similar to allow air to be drawn up the chimney.

Open fires and chimneys act as a kind of air extraction system. As warm air rises from the fire it draws air out of the room, and the house. Couple that with the heat of a fire and you have a surprisingly effective air exchanger which can help reduce damp.

 

[richardmm]

Air needs to flow through a chimney - you need a hole at the top and the bottom to create a draw, like a fire needs. You need an air brick or similar to allow air to be drawn up the chimney.

Open fires and chimneys act as a kind of air extraction system. As warm air rises from the fire it draws air out of the room, and the house. Couple that with the heat of a fire and you have a surprisingly effective air exchanger which can help reduce damp.

good person i see this thread no reply for 3 days and i think no one helping much maybe there are greedy but you help i appreciate but
question is why chimney get damp then? if no leaking water pipe is inside chimney then why chimney get automatically damp?

if there is nothing causing the water inside chimney then why is damp automatic come? i have no water in chimney then why will damp come? i need know the physic behind it?

 

[mikeey84]

Chimneys get damp as they are subject to rain ingress, both through the top, and potentially soaking through the brickwork.

Additionally, water contains a certain % of water (measured by humidity), and old chimneys full of soot, which attract water due to the high salt content.

Good airflow helps prevent the dampness getting high enough to show through the chimney breast

 

[noseall]

if there is nothing causing the water inside chimney then why is damp automatic come? i have no water in chimney then why will damp come? i need know the physic behind it?

Hygroscopic salt saturation to the masonry, due to burning fossil fuels. It means the masonry, can attract moisture.

 

[richardmm]

Hygroscopic salt saturation to the masonry, due to burning fossil fuels. It means the masonry, can attract moisture.

but the chimney remains open from top side roof so why do i neeed air ?

 

[richardmm]

already the chimney get air from top of roof

 

[mikeey84]

You need air flow, ie moving air. With only the top open, the air at the bottom of the chimney won't move anywhere

 

[richardmm]

but why my chimney not damp because my living room chimney is blocked up but the front room one is open so why did it not gfet damp for 20 years?

 

[mikeey84]

Buildings deteriorate over time. Things that are fine for years can start showing damp or damage over night after a gradual build up